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Data science
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Data science is an interdisciplinary academic field[1] that uses statistics, scientific computing, scientific methods, processing, scientific visualization, algorithms and systems to extract or extrapolate knowledge from potentially noisy, structured, or unstructured data.[2]
Data science also integrates domain knowledge from the underlying application domain (e.g., natural sciences, information technology, and medicine).[3] Data science is multifaceted and can be described as a science, a research paradigm, a research method, a discipline, a workflow, and a profession.[4]
Data science is "a concept to unify statistics, data analysis, informatics, and their related methods" to "understand and analyze actual phenomena" with data.[5] It uses techniques and theories drawn from many fields within the context of mathematics, statistics, computer science, information science, and domain knowledge.[6] However, data science is different from computer science and information science. Turing Award winner Jim Gray imagined data science as a "fourth paradigm" of science (empirical, theoretical, computational, and now data-driven) and asserted that "everything about science is changing because of the impact of information technology" and the data deluge.[7][8]
A data scientist is a professional who creates programming code and combines it with statistical knowledge to summarize data.[9]
Foundations
[edit]Data science is an interdisciplinary field[10] focused on extracting knowledge from typically large data sets and applying the knowledge from that data to solve problems in other application domains. The field encompasses preparing data for analysis, formulating data science problems, analyzing data, and summarizing these findings. As such, it incorporates skills from computer science, mathematics, data visualization, graphic design, communication, and business.[11]
Vasant Dhar writes that statistics emphasizes quantitative data and description. In contrast, data science deals with quantitative and qualitative data (e.g., from images, text, sensors, transactions, customer information, etc.) and emphasizes prediction and action.[12] Andrew Gelman of Columbia University has described statistics as a non-essential part of data science.[13] Stanford professor David Donoho writes that data science is not distinguished from statistics by the size of datasets or use of computing and that many graduate programs misleadingly advertise their analytics and statistics training as the essence of a data-science program. He describes data science as an applied field growing out of traditional statistics.[14]
Etymology
[edit]Early usage
[edit]In 1962, John Tukey described a field he called "data analysis", which resembles modern data science.[14] In 1985, in a lecture given to the Chinese Academy of Sciences in Beijing, C. F. Jeff Wu used the term "data science" for the first time as an alternative name for statistics.[15] Later, attendees at a 1992 statistics symposium at the University of Montpellier II acknowledged the emergence of a new discipline focused on data of various origins and forms, combining established concepts and principles of statistics and data analysis with computing.[16][17]
The term "data science" has been traced back to 1974, when Peter Naur proposed it as an alternative name to computer science. In his 1974 book Concise Survey of Computer Methods, Peter Naur proposed using the term ‘data science’ rather than ‘computer science’ to reflect the growing emphasis on data-driven methods[18][6] In 1996, the International Federation of Classification Societies became the first conference to specifically feature data science as a topic.[6] However, the definition was still in flux. After the 1985 lecture at the Chinese Academy of Sciences in Beijing, in 1997 C. F. Jeff Wu again suggested that statistics should be renamed data science. He reasoned that a new name would help statistics shed inaccurate stereotypes, such as being synonymous with accounting or limited to describing data.[19] In 1998, Hayashi Chikio argued for data science as a new, interdisciplinary concept, with three aspects: data design, collection, and analysis.[17]
Modern usage
[edit]In 2012, technologists Thomas H. Davenport and DJ Patil declared "Data Scientist: The Sexiest Job of the 21st Century",[20] a catchphrase that was picked up even by major-city newspapers like the New York Times[21] and the Boston Globe.[22] A decade later, they reaffirmed it, stating that "the job is more in demand than ever with employers".[23]
The modern conception of data science as an independent discipline is sometimes attributed to William S. Cleveland.[24] In 2014, the American Statistical Association's Section on Statistical Learning and Data Mining changed its name to the Section on Statistical Learning and Data Science, reflecting the ascendant popularity of data science.[25]
The professional title of "data scientist" has been attributed to DJ Patil and Jeff Hammerbacher in 2008.[26] Though it was used by the National Science Board in their 2005 report "Long-Lived Digital Data Collections: Enabling Research and Education in the 21st Century", it referred broadly to any key role in managing a digital data collection.[27]
Data science and data analysis
[edit]
In data science, data analysis is the process of inspecting, cleaning, transforming, and modelling data to discover useful information, draw conclusions, and support decision-making.[28] It includes exploratory data analysis (EDA), which uses graphics and descriptive statistics to explore patterns and generate hypotheses,[29] and confirmatory data analysis, which applies statistical inference to test hypotheses and quantify uncertainty.[30]
Typical activities comprise:
- data collection and integration;
- data cleaning and preparation (handling missing values, outliers, encoding, normalisation);
- feature engineering and selection;
- visualisation and descriptive statistics;[29]
- fitting and evaluating statistical or machine-learning models;[30]
- communicating results and ensuring reproducibility (e.g., reports, notebooks, and dashboards).[31]
Lifecycle frameworks such as CRISP-DM describe these steps from business understanding through deployment and monitoring.[32]
Data science involves working with larger datasets that often require advanced computational and statistical methods to analyze. Data scientists often work with unstructured data such as text or images and use machine learning algorithms to build predictive models. Data science often uses statistical analysis, data preprocessing, and supervised learning.[33][34]
Cloud computing for data science
[edit]
Cloud computing can offer access to large amounts of computational power and storage.[35] In big data, where volumes of information are continually generated and processed, these platforms can be used to handle complex and resource-intensive analytical tasks.[36]
Some distributed computing frameworks are designed to handle big data workloads. These frameworks can enable data scientists to process and analyze large datasets in parallel, which can reduce processing times.[37]
Ethical consideration in data science
[edit]Data science involves collecting, processing, and analyzing data which often includes personal and sensitive information. Ethical concerns include potential privacy violations, bias perpetuation, and negative societal impacts.[38][39]
Machine learning models can amplify existing biases present in training data, leading to discriminatory or unfair outcomes.[40][41]
See also
[edit]- Python (programming language)
- R (programming language)
- Data engineering
- Big data
- Machine learning
- Artificial intelligence
- Bioinformatics
- Astroinformatics
- Topological data analysis
- List of data science journals
- List of data science software
- List of open-source data science software
- Data science notebook software
References
[edit]- ^ Donoho, David (2017). "50 Years of Data Science". Journal of Computational and Graphical Statistics. 26 (4): 745–766. doi:10.1080/10618600.2017.1384734. S2CID 114558008.
- ^ Dhar, V. (2013). "Data science and prediction". Communications of the ACM. 56 (12): 64–73. doi:10.1145/2500499. S2CID 6107147. Archived from the original on 9 November 2014. Retrieved 2 September 2015.
- ^ Danyluk, A.; Leidig, P. (2021). Computing Competencies for Undergraduate Data Science Curricula (PDF). ACM Data Science Task Force Final Report (Report).
- ^ Mike, Koby; Hazzan, Orit (20 January 2023). "What is Data Science?". Communications of the ACM. 66 (2): 12–13. doi:10.1145/3575663. ISSN 0001-0782.
- ^ Hayashi, Chikio (1 January 1998). "What is Data Science ? Fundamental Concepts and a Heuristic Example". In Hayashi, Chikio; Yajima, Keiji; Bock, Hans-Hermann; Ohsumi, Noboru; Tanaka, Yutaka; Baba, Yasumasa (eds.). Data Science, Classification, and Related Methods. Studies in Classification, Data Analysis, and Knowledge Organization. Springer Japan. pp. 40–51. doi:10.1007/978-4-431-65950-1_3. ISBN 978-4-431-70208-5.
- ^ a b c Cao, Longbing (29 June 2017). "Data Science: A Comprehensive Overview". ACM Computing Surveys. 50 (3): 43:1–43:42. arXiv:2007.03606. doi:10.1145/3076253. ISSN 0360-0300. S2CID 207595944.
- ^ Tony Hey; Stewart Tansley; Kristin Michele Tolle (2009). The Fourth Paradigm: Data-intensive Scientific Discovery. Microsoft Research. ISBN 978-0-9825442-0-4. Archived from the original on 20 March 2017.
- ^ Bell, G.; Hey, T.; Szalay, A. (2009). "Computer Science: Beyond the Data Deluge". Science. 323 (5919): 1297–1298. doi:10.1126/science.1170411. ISSN 0036-8075. PMID 19265007. S2CID 9743327.
- ^ Davenport, Thomas H.; Patil, D. J. (October 2012). "Data Scientist: The Sexiest Job of the 21st Century". Harvard Business Review. 90 (10): 70–76, 128. PMID 23074866. Retrieved 18 January 2016.
- ^ Emmert-Streib, Frank; Dehmer, Matthias (2018). "Defining data science by a data-driven quantification of the community". Machine Learning and Knowledge Extraction. 1: 235–251. doi:10.3390/make1010015.
- ^ "1. Introduction: What Is Data Science?". Doing Data Science [Book]. O'Reilly. Retrieved 3 April 2020.
- ^ Vasant Dhar (1 December 2013). "Data science and prediction". Communications of the ACM. 56 (12): 64–73. doi:10.1145/2500499. S2CID 6107147.
- ^ "Statistics is the least important part of data science « Statistical Modeling, Causal Inference, and Social Science". statmodeling.stat.columbia.edu. Retrieved 3 April 2020.
- ^ a b Donoho, David (18 September 2015). "50 years of Data Science" (PDF). Retrieved 2 April 2020.
- ^ Wu, C. F. Jeff (1986). "Future directions of statistical research in China: a historical perspective" (PDF). Application of Statistics and Management. 1: 1–7. Retrieved 29 November 2020.
- ^ Escoufier, Yves; Hayashi, Chikio; Fichet, Bernard, eds. (1995). Data science and its applications. Tokyo: Academic Press/Harcourt Brace. ISBN 0-12-241770-4. OCLC 489990740.
- ^ a b Murtagh, Fionn; Devlin, Keith (2018). "The Development of Data Science: Implications for Education, Employment, Research, and the Data Revolution for Sustainable Development". Big Data and Cognitive Computing. 2 (2): 14. doi:10.3390/bdcc2020014.
- ^ https://seas.harvard.edu/news/what-data-science-definition-skills-applications-more
- ^ Wu, C. F. Jeff. "Statistics=Data Science?" (PDF). Retrieved 2 April 2020.
- ^ Davenport, Thomas (1 October 2012). "Data Scientist: The Sexiest Job of the 21st Century". Harvard Business Review. Retrieved 10 October 2022.
- ^ Miller, Claire (4 April 2013). "Data Science: The Numbers of Our Lives". New York Times. New York City. Retrieved 10 October 2022.
- ^ Borchers, Callum (11 November 2015). "Behind the scenes of the 'sexiest job of the 21st century'". Boston Globe. Boston. Retrieved 10 October 2022.
- ^ Davenport, Thomas (15 July 2022). "Is Data Scientist Still the Sexiest Job of the 21st Century?". Harvard Business Review. Retrieved 10 October 2022.
- ^ William S. Cleveland (April 2001). "Data Science: an Action Plan for Expanding the Technical Areas of the Field of Statistics". International Statistical Review. 69 (1): 21–26. doi:10.1111/J.1751-5823.2001.TB00477.X. ISSN 0306-7734. JSTOR 1403527. S2CID 39680861. Zbl 1213.62003. Wikidata Q134576907.
- ^ Talley, Jill (1 June 2016). "ASA Expands Scope, Outreach to Foster Growth, Collaboration in Data Science". Amstat News. American Statistical Association.. In 2013 the first European Conference on Data Analysis (ECDA2013) started in Luxembourg the process which founded the European Association for Data Science (EuADS) www.euads.org in Luxembourg in 2015.
- ^ Davenport, Thomas H.; Patil, D. J. (1 October 2012). "Data Scientist: The Sexiest Job of the 21st Century". Harvard Business Review. No. October 2012. ISSN 0017-8012. Retrieved 3 April 2020.
- ^ "US NSF – NSB-05-40, Long-Lived Digital Data Collections Enabling Research and Education in the 21st Century". www.nsf.gov. Retrieved 3 April 2020.
- ^ Spiegelhalter, David (2019). The Art of Statistics: How to Learn from Data. Basic Books. ISBN 978-1-5416-1851-0.
- ^ a b Tukey, John W. (1977). Exploratory Data Analysis. Addison-Wesley. ISBN 978-0-201-07616-5.
- ^ a b James, Gareth; Witten, Daniela; Hastie, Trevor; Tibshirani, Robert (2017). An Introduction to Statistical Learning: with Applications in R. Springer. ISBN 978-1-4614-7137-0.
- ^ O'Neil, Cathy; Schutt, Rachel (2013). Doing Data Science. O'Reilly Media. ISBN 978-1-4493-5865-5.
- ^ CRISP-DM 1.0: Step-by-step data mining guide (Report). SPSS. 2000.
- ^ Provost, Foster; Tom Fawcett (1 August 2013). "Data Science for Business: What You Need to Know about Data Mining and Data-Analytic Thinking". O'Reilly Media, Inc.
- ^ Han, Kamber; Pei (2011). Data Mining: Concepts and Techniques. ISBN 978-0-12-381479-1.
- ^ Hashem, Ibrahim Abaker Targio; Yaqoob, Ibrar; Anuar, Nor Badrul; Mokhtar, Salimah; Gani, Abdullah; Ullah Khan, Samee (2015). "The rise of "big data" on cloud computing: Review and open research issues". Information Systems. 47: 98–115. doi:10.1016/j.is.2014.07.006.
- ^ Qiu, Junfei; Wu, Qihui; Ding, Guoru; Xu, Yuhua; Feng, Shuo (2016). "A survey of machine learning for big data processing". EURASIP Journal on Advances in Signal Processing. 2016 (1). doi:10.1186/s13634-016-0355-x. ISSN 1687-6180.
- ^ Armbrust, Michael; Xin, Reynold S.; Lian, Cheng; Huai, Yin; Liu, Davies; Bradley, Joseph K.; Meng, Xiangrui; Kaftan, Tomer; Franklin, Michael J.; Ghodsi, Ali; Zaharia, Matei (27 May 2015). "Spark SQL: Relational Data Processing in Spark". Proceedings of the 2015 ACM SIGMOD International Conference on Management of Data. ACM. pp. 1383–1394. doi:10.1145/2723372.2742797. ISBN 978-1-4503-2758-9.
- ^ Floridi, Luciano; Taddeo, Mariarosaria (28 December 2016). "What is data ethics?". Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences. 374 (2083) 20160360. Bibcode:2016RSPTA.37460360F. doi:10.1098/rsta.2016.0360. ISSN 1364-503X. PMC 5124072. PMID 28336805.
- ^ Mittelstadt, Brent Daniel; Floridi, Luciano (2016). "The Ethics of Big Data: Current and Foreseeable Issues in Biomedical Contexts". Science and Engineering Ethics. 22 (2): 303–341. doi:10.1007/s11948-015-9652-2. ISSN 1353-3452. PMID 26002496.
- ^ Barocas, Solon; Selbst, Andrew D (2016). "Big Data's Disparate Impact". California Law Review. doi:10.15779/Z38BG31 – via Berkeley Law Library Catalog.
- ^ Caliskan, Aylin; Bryson, Joanna J.; Narayanan, Arvind (14 April 2017). "Semantics derived automatically from language corpora contain human-like biases". Science. 356 (6334): 183–186. arXiv:1608.07187. Bibcode:2017Sci...356..183C. doi:10.1126/science.aal4230. ISSN 0036-8075.
Data science
View on GrokipediaHistorical Development
Origins in Statistics and Early Computing
The foundations of data science lie in the evolution of statistical methods during the late 19th and early 20th centuries, which provided tools for summarizing and inferring from data, coupled with mechanical and electronic computing innovations that scaled these processes beyond manual limits. Pioneers such as Karl Pearson, who developed correlation coefficients and chi-squared tests around 1900, and Ronald Fisher, who formalized analysis of variance (ANOVA) in the 1920s, established inferential frameworks essential for data interpretation.[4][13] These advancements emphasized empirical validation over theoretical abstraction, enabling causal insights from observational data when randomized experiments were infeasible. A pivotal shift occurred in 1962 when John Tukey published "The Future of Data Analysis" in the Annals of Mathematical Statistics, distinguishing data analysis as exploratory procedures for uncovering structures in data from confirmatory statistical inference.[14] Tukey argued that data analysis should prioritize robust, graphical, and iterative techniques to reveal hidden patterns, critiquing overreliance on asymptotic theory ill-suited to finite, noisy datasets.[15] This work, spanning 67 pages, highlighted the need for computational aids to implement "vacuum cleaner" methods that sift through data without preconceived models, influencing later exploratory data analysis practices.[16] Early computing complemented statistics by automating tabulation and calculation. In 1890, Herman Hollerith's punched-card tabulating machine processed U.S. Census data, reducing analysis time from years to months and handling over 60 million cards for demographic variables like age, sex, and occupation.[17] By the 1920s and 1930s, IBM's mechanical sorters and tabulators were adopted in universities for statistical aggregation, fostering dedicated statistical computing courses and enabling multivariate analyses previously constrained by hand computation.[18] Post-World War II electronic computers accelerated this integration. The ENIAC, completed in 1945, performed high-speed arithmetic for ballistic and scientific simulations, including early statistical modeling in operations research.[19] At Bell Labs, Tukey contributed to statistical applications on these machines, coining the term "bit" in 1947 to quantify information in computational contexts.[20] By the 1960s, software libraries like the International Mathematical and Statistical Libraries (IMSL) emerged for Fortran-based statistical routines, while packages such as SAS (1966) and SPSS (1968) democratized regression, ANOVA, and factor analysis on mainframes.[21] This era's computational scalability revealed statistics' limitations in high-dimensional data, prompting interdisciplinary approaches that presaged data science's emphasis on algorithmic processing over purely probabilistic models.Etymology and Emergence as a Discipline
The term "data science" first appeared in print in 1974, when Danish computer scientist Peter Naur used it as an alternative to "computer science" in his book Concise Survey of Computer Methods, framing it around the systematic processing, storage, and analysis of data via computational tools.[1] This early usage highlighted data handling as central to computing but did not yet delineate a separate field, remaining overshadowed by established disciplines like statistics and informatics.[4] Renewed interest emerged in the late 1990s amid debates over reorienting statistics to address exploding data volumes from digital systems. Statistician C. F. Jeff Wu argued in a 1997 presentation that "data science" better captured the field's evolution, proposing it as a rebranding for statistics to encompass broader computational and applied dimensions beyond traditional inference.[22] The term gained formal traction in 2001 through William S. Cleveland's article "Data Science: An Action Plan for Expanding the Technical Areas of the Field of Statistics," published in the International Statistical Review. Cleveland positioned data science as an extension of statistics, integrating machine learning, data mining, and scalable computation to manage heterogeneous, high-volume datasets; he specified six core areas—multivariate analysis, data mining, local modeling, robust methods, visualization, and data management—as foundational for training data professionals.[23][24] This blueprint addressed gaps in statistics curricula, which Cleveland noted inadequately covered computational demands driven by enterprise data growth.[25] Data science coalesced as a distinct discipline in the 2000s, propelled by big data proliferation from web-scale computing and storage advances. The National Science Board emphasized in a 2005 report the urgent need for specialists in large-scale data handling, marking institutional acknowledgment of its interdisciplinary scope spanning statistics, computer science, and domain expertise.[26] By the early 2010s, universities established dedicated programs; for instance, UC Berkeley graduated its inaugural data science majors in 2018, following earlier master's initiatives that integrated statistical rigor with programming and algorithmic tools.[27] This emergence reflected causal drivers like exponential data growth—global datasphere reaching 2 zettabytes by 2010—and demands for predictive modeling in sectors such as finance and genomics, differentiating data science from statistics via its focus on end-to-end pipelines for actionable insights from unstructured data.[4]Key Milestones and Pioneers
In 1962, John W. Tukey published "The Future of Data Analysis" in the Annals of Mathematical Statistics, distinguishing data analysis from confirmatory statistical inference and advocating for exploratory techniques to uncover patterns in data through visualization and iterative examination.[14] Tukey, a mathematician and statistician at Princeton and Bell Labs, emphasized procedures for interpreting data results, laying groundwork for modern data exploration practices.[15] The 1970s saw foundational advances in data handling, including the development of relational database management systems by Edgar F. Codd at IBM in 1970, which enabled structured querying of large datasets via SQL formalized in 1974.[28] These innovations supported scalable data storage and retrieval, essential for subsequent data-intensive workflows. In 2001, William S. Cleveland proposed "data science" as an expanded technical domain within statistics in his article "Data Science: An Action Plan for Expanding the Technical Areas of the Field of Statistics," published in the International Statistical Review.[23] Cleveland, then at Bell Labs, outlined six areas—data exploration, statistical modeling, computation, data management, interfaces, and scientific learning—to integrate computing and domain knowledge, arguing for university departments to allocate resources accordingly.[29] The term "data scientist" as a professional title emerged around 2008, attributed to DJ Patil at LinkedIn and Jeff Hammerbacher at Facebook, who applied statistical and computational methods to business problems amid growing internet-scale data.[30] This role gained prominence in 2012 with Thomas Davenport and D.J. Patil's Harvard Business Review article dubbing it "the sexiest job of the 21st century," reflecting demand for interdisciplinary expertise in machine learning and analytics.[13] Other contributors include Edward Tufte, whose 1983 book The Visual Display of Quantitative Information advanced principles for effective data visualization, influencing how pioneers like Tukey’s exploratory methods are implemented.[13] These milestones trace data science's evolution from statistical roots to a distinct field bridging computation, statistics, and domain application.Theoretical Foundations
Statistical and Mathematical Underpinnings
Data science draws fundamentally from probability theory to quantify uncertainty, model random phenomena, and derive probabilistic predictions from data. Core concepts include random variables, probability distributions such as the normal and binomial, and laws like the central limit theorem, which justify approximating sample statistics for population inferences under large sample sizes. These elements enable handling noisy, incomplete datasets prevalent in real-world applications, where outcomes are stochastic rather than deterministic.[31][32] Statistical inference forms the inferential backbone, encompassing point estimation, interval estimation, and hypothesis testing to assess whether observed patterns reflect genuine population characteristics or arise from sampling variability. Techniques like p-values, confidence intervals, and likelihood ratios allow data scientists to evaluate model fit and generalizability, though reliance on frequentist methods can overlook prior knowledge, prompting Bayesian alternatives that incorporate priors for updated beliefs via Bayes' theorem. Empirical validation remains paramount, as inference pitfalls—such as multiple testing biases inflating false positives—necessitate corrections like Bonferroni adjustments to maintain rigor.[33][34][35] Linear algebra provides the algebraic structure for representing and transforming high-dimensional data, with vectors denoting observations and matrices encoding feature relationships or covariance structures. Operations like matrix multiplication underpin algorithms for regression and clustering, while decompositions such as singular value decomposition (SVD) enable dimensionality reduction, compressing data while preserving variance—critical for managing the curse of dimensionality in large datasets. Eigenvalue problems further support spectral methods in graph analytics and principal component analysis (PCA), revealing latent structures without assuming causality.[36][37] Multivariate calculus and optimization theory drive parameter estimation in predictive models, particularly through gradient-based methods that minimize empirical risk via loss functions like mean squared error. Stochastic gradient descent (SGD), an iterative optimizer, scales to massive datasets by approximating full gradients with minibatches, converging under convexity assumptions or with momentum variants for non-convex landscapes common in deep learning. Convex optimization guarantees global minima for linear and quadratic programs, but data science often navigates non-convexity via heuristics, underscoring the need for convergence diagnostics and regularization to prevent overfitting.[38][39] These underpinnings intersect in frameworks like generalized linear models, where probability governs error distributions, inference tests coefficients, linear algebra solves via least squares, and optimization handles constraints—yet causal identification requires beyond-association reasoning, as correlations from observational data may confound true effects without experimental controls or instrumental variables.[40][35]Computational and Informatic Components
Computational components of data science encompass algorithms and models of computation designed to process, analyze, and learn from large-scale data efficiently. Central to this is computational complexity theory, which quantifies the time and space resources required by algorithms as a function of input size, typically expressed in Big O notation to describe worst-case asymptotic behavior. For instance, sorting algorithms like quicksort operate in O(n log n) time on average, enabling efficient preprocessing of datasets with millions of records, while exponential-time algorithms are impractical for high-dimensional data common in data science tasks.[41] Many core problems, such as k-means clustering, are NP-hard, meaning exact solutions require time exponential in the number of clusters k, prompting reliance on approximation algorithms that achieve near-optimal results in polynomial time.[42] Singular value decomposition (SVD) exemplifies efficient computational techniques for dimensionality reduction and latent structure discovery, factorizing a matrix A into UDV^T where the top-k singular values yield the best low-rank approximation minimizing Frobenius norm error; this can be computed approximately via the power method in polynomial time even for sparse matrices exceeding 10^8 dimensions.[42] Streaming algorithms further address big data constraints by processing sequential inputs in one pass with sublinear space, such as hashing-based estimators for distinct element counts using O(log m) space where m is the universe size.[42] Probably approximately correct (PAC) learning frameworks bound sample complexity for consistent hypothesis learning, requiring O(1/ε (log |H| + log(1/δ))) examples to achieve error ε with probability 1-δ over hypothesis class H.[42] Informatic components draw from information theory to quantify data uncertainty, redundancy, and dependence, underpinning tasks like compression and inference. Entropy, defined as H(X) = -∑ p(x) log₂ p(x), measures the average bits needed to encode random variable X, serving as a foundational metric for data distribution unpredictability and lossy compression limits via the source coding theorem.[43] Mutual information I(X;Y) = H(X) - H(X|Y) captures shared information between variables, enabling feature selection by prioritizing attributes that maximally reduce target entropy, as in greedy algorithms that iteratively select features maximizing I(Y; selected features).[44] These measures inform model evaluation, such as Kullback-Leibler divergence for comparing distributions in generative modeling, ensuring algorithms exploit data structure without unnecessary redundancy.[44] In practice, information-theoretic bounds guide scalable informatics, like variable-length coding in data storage, where Huffman algorithms achieve entropy rates for prefix-free encoding.[45]Distinctions from Related Disciplines
Data Science versus Data Analysis
Data science represents an interdisciplinary field that applies scientific methods, algorithms, and computational techniques to derive knowledge and insights from potentially noisy, structured, or unstructured data, often emphasizing predictive modeling, automation, and scalable systems.[46] Data analysis, by comparison, focuses on the systematic examination of existing datasets to summarize key characteristics, detect patterns, and support decision-making through descriptive statistics, visualization, and inferential techniques, typically without extensive model deployment or handling of massive-scale data.[47] This distinction emerged prominently in the early 2010s as organizations distinguished roles requiring advanced programming and machine learning from traditional analytical tasks, with data analysis tracing roots to statistical practices predating the term "data science," which was popularized in 2008 by DJ Patil and Jeff Hammerbacher to describe professionals bridging statistics and software engineering at companies like LinkedIn and Facebook. A primary difference lies in scope and objectives: data science pursues forward-looking predictions and prescriptions by integrating machine learning algorithms to forecast outcomes and optimize processes, such as using regression models or neural networks on large datasets to anticipate customer churn with accuracies exceeding 80% in controlled benchmarks.[48][49] Data analysis, conversely, centers on retrospective and diagnostic insights, employing tools like hypothesis testing or correlation analysis to explain historical trends, as seen in exploratory data analysis (EDA) workflows that reveal data quality issues or outliers via visualizations before deeper modeling.[50] For instance, while a data analyst might use SQL queries on relational databases to generate quarterly sales reports identifying a 15% year-over-year decline attributable to seasonal factors, a data scientist would extend this to build deployable ensemble models incorporating external variables like economic indicators for ongoing forecasting.[51] Skill sets further delineate the fields: data scientists typically require proficiency in programming languages such as Python or R for scripting complex pipelines, alongside expertise in libraries like scikit-learn for machine learning and TensorFlow for deep learning, enabling handling of petabyte-scale data via distributed computing frameworks.[49] Data analysts, however, prioritize domain-specific tools including Excel for pivot tables, Tableau for interactive dashboards, and basic statistical software, focusing on data cleaning and reporting without mandatory coding depth—evidenced by job postings from 2020-2024 showing data analyst roles demanding SQL in 70% of cases versus Python in under 30%, compared to over 90% for data scientists.[48][46] Methodologically, data science incorporates iterative cycles of experimentation, including feature engineering, hyperparameter tuning, and A/B testing for causal inference, often validated against holdout sets to achieve metrics like AUC-ROC scores above 0.85 in classification tasks.[52] Data analysis workflows, in contrast, emphasize confirmatory analysis and visualization to validate assumptions, such as using box plots or heatmaps to assess normality in datasets of thousands of records, but rarely extend to automated retraining or production integration.[53] Overlap exists, as data analysis forms an initial phase in data science pipelines—comprising up to 80% of a data scientist's time on preparation per industry surveys—but the former lacks the engineering rigor for scalable, real-time applications like recommendation engines processing millions of queries per second.[47]| Aspect | Data Science | Data Analysis |
|---|---|---|
| Focus | Predictive and prescriptive modeling; future-oriented insights | Descriptive and diagnostic summaries; past/present patterns |
| Tools/Techniques | Python/R, ML algorithms (e.g., random forests), big data platforms (e.g., Spark) | SQL/Excel, BI tools (e.g., Power BI), basic stats (e.g., t-tests) |
| Data Scale | Handles unstructured/big data volumes (terabytes+) | Primarily structured datasets (gigabytes or less) |
| Outcomes | Deployable models, automation (e.g., API-integrated forecasts) | Reports, dashboards for immediate business intelligence |
Data Science versus Statistics and Machine Learning
Data science encompasses statistics and machine learning as core components but extends beyond them through an interdisciplinary approach that integrates substantial computational engineering, domain-specific knowledge, and practical workflows for extracting actionable insights from large-scale, often unstructured data. Whereas statistics primarily emphasizes theoretical inference, probabilistic modeling, and hypothesis testing to draw generalizable conclusions about populations from samples, data science applies these methods within broader pipelines that prioritize scalable implementation and real-world deployment. Machine learning, conversely, centers on algorithmic techniques for pattern recognition and predictive modeling, often optimizing for accuracy over interpretability, particularly with high-dimensional datasets; data science incorporates machine learning as a modeling tool but subordinates it to end-to-end processes including data ingestion, cleaning, feature engineering, and iterative validation.[54][55][56] This distinction traces to foundational proposals, such as William S. Cleveland's 2001 action plan, which advocated expanding statistics into "data science" by incorporating multistructure data handling, data mining, and computational tools to address limitations in traditional statistical practice amid growing data volumes from digital sources. Cleveland argued that statistics alone insufficiently equipped practitioners for the "data explosion" requiring robust software interfaces and algorithmic scalability, positioning data science as an evolution rather than a replacement. In contrast, machine learning's roots in computational pattern recognition—exemplified by early neural networks and decision trees developed in the 1980s and 1990s—focus on automation of prediction tasks, with less emphasis on causal inference or distributional assumptions central to statistics. Empirical surveys of job requirements confirm these divides: data science roles demand proficiency in programming (e.g., Python or R for ETL processes) and systems integration at rates exceeding 70% of postings, while pure statistics positions prioritize mathematical proofs and experimental design, and machine learning engineering stresses optimization of models like gradient boosting or deep learning frameworks.[23][24][57] Critics, including some statisticians, contend that data science largely rebrands applied statistics with added software veneer, potentially diluting rigor in favor of "hacking" expediency; however, causal analyses of project outcomes reveal data science's advantage in handling non-iid data and iterative feedback loops, where statistics' parametric assumptions falter and machine learning's black-box predictions require contextual interpretation absent in isolated ML workflows. For instance, in predictive maintenance applications, data scientists leverage statistical validation (e.g., confidence intervals) alongside machine learning forecasts (e.g., via random forests) within engineered pipelines processing terabyte-scale sensor data, yielding error reductions of 20-30% over siloed approaches. Machine learning's predictive focus aligns with data science's goals but lacks the holistic emphasis on data quality assurance—estimated to consume 60-80% of data science effort—and stakeholder communication, underscoring why data science curricula integrate all three domains without subsuming to either. Overlaps persist, as advanced machine learning increasingly adopts statistical regularization techniques, yet the fields diverge in scope: statistics for foundational uncertainty quantification, machine learning for scalable approximation, and data science for synthesized, evidence-based decision systems.[58][59]Methodologies and Workflow
Data Acquisition and Preparation
Data acquisition in data science refers to the process of gathering raw data from various sources to support analysis and modeling. Primary methods include collecting new data through direct measurement via sensors or experiments, converting and transforming existing legacy data into usable formats, sharing or exchanging data with collaborators, and purchasing datasets from third-party providers.[60] These approaches ensure access to empirical observations, but challenges arise from data volume, velocity, and variety, often requiring automated tools for efficient ingestion from databases, APIs, or streaming sources like IoT devices.[61] Legal and ethical considerations, such as privacy regulations under laws like GDPR and copyrights, constrain acquisition by limiting usable data and necessitating consent or anonymization protocols.[62] In practice, acquisition prioritizes authoritative sources to minimize bias, with techniques like selective sampling used to optimize costs and relevance in machine learning pipelines.[63] Data preparation, often consuming 80-90% of a data science workflow, transforms acquired raw data into a clean, structured form suitable for modeling.[64] Key steps involve exploratory data analysis (EDA) to visualize distributions and relationships, revealing issues like the misleading uniformity of summary statistics across visually distinct datasets, as demonstrated by the Datasaurus Dozen.[65] Cleaning addresses common data quality issues: duplicates are identified and removed using hashing or record linkage algorithms; missing values are handled via deletion, mean/median imputation, or advanced methods like k-nearest neighbors; outliers are detected through statistical tests (e.g., Z-score > 3) or robust models and either winsorized or investigated for causal validity.[66] Peer-reviewed frameworks emphasize iterative screening for these errors before analysis to enhance replicability and reduce model bias.[67] Transformation follows cleaning, encompassing normalization (e.g., min-max scaling to [0,1]), standardization (z-score to mean 0, variance 1), categorical encoding (one-hot or ordinal), and feature engineering to derive causal or predictive variables from raw inputs.[68] Integration merges disparate sources, resolving schema mismatches via entity resolution, while validation checks ensure consistency, such as range bounds and referential integrity.[69] Poor preparation propagates errors, inflating false positives in downstream inference, underscoring the need for version-controlled pipelines in reproducible science.[70]Modeling, Analysis, and Validation
In data science workflows, modeling entails constructing mathematical representations of data relationships using techniques such as linear regression for continuous outcomes, logistic regression for binary classification, and ensemble methods like random forests for improved predictive accuracy.[71] Supervised learning dominates when labeled data is available, training models to minimize empirical risk via optimization algorithms like gradient descent, while unsupervised approaches, including k-means clustering and principal component analysis, identify inherent structures without predefined targets.[72] Model selection often involves balancing bias and variance, as excessive complexity risks overfitting, where empirical evidence from deep neural networks on electronic health records demonstrates performance degradation on unseen data due to memorization of training noise rather than generalization.[73][72] Analysis follows modeling to interpret results and extract insights, employing methods like partial dependence plots to assess feature impacts and SHAP values for attributing predictions to individual inputs in tree-based models.[74] Hypothesis testing, such as t-tests on coefficient significance, quantifies uncertainty, while sensitivity analyses probe robustness to perturbations in inputs or assumptions. In causal contexts, mere predictive modeling risks conflating correlation with causation; techniques like difference-in-differences or instrumental variables are integrated to estimate treatment effects, as observational data often harbors confounders that invalidate naive associations.[75] For instance, propensity score matching adjusts for selection bias by balancing covariate distributions across treated and control groups, enabling more reliable causal claims in non-experimental settings.[75] Validation rigorously assesses model reliability through techniques like k-fold cross-validation, which partitions data into k subsets to iteratively train and test, yielding unbiased estimates of out-of-sample error; empirical studies confirm its superiority over simple train-test splits in mitigating variance under limited data.[76] Performance metrics include mean squared error for regression tasks, F1-score for imbalanced classification, and area under the ROC curve for probabilistic outputs, with thresholds calibrated to domain costs—e.g., false positives in medical diagnostics warrant higher penalties.[74] Bootstrap resampling provides confidence intervals for these metrics, while external validation on independent datasets detects temporal or distributional shifts, as seen in production failures where models trained on pre-2020 data underperform post-pandemic due to covariate changes.[72] Overfitting is diagnosed via learning curves showing training-test divergence, prompting regularization like L1/L2 penalties or early stopping, which empirical benchmarks on UCI datasets reduce error by 10-20% in high-dimensional settings.[73]Deployment and Iteration
Deployment in data science entails transitioning validated models from development environments to production systems capable of serving predictions at scale, often through machine learning operations (MLOps) frameworks that automate integration, testing, and release processes.[77] MLOps adapts DevOps principles to machine learning workflows, incorporating continuous integration for code and data, continuous delivery for model artifacts, and continuous training to handle iterative updates.[78] Common deployment strategies include containerization using Docker to package models with dependencies, followed by orchestration with Kubernetes for managing scalability and fault tolerance in cloud environments.[79] Real-time inference typically employs RESTful APIs or serverless functions, while batch processing suits periodic jobs; for instance, Azure Machine Learning supports endpoint deployment for low-latency predictions.[80] Empirical studies highlight persistent challenges in deployment, such as integrating models with existing infrastructure and ensuring reproducibility, with a 2022 survey of case studies across industries identifying legacy system compatibility and versioning inconsistencies as frequent barriers.[81] An arXiv analysis of asset management in ML pipelines revealed software dependencies and deployment orchestration as top issues, affecting over 20% of reported challenges in practitioner surveys.[82] To mitigate these, best practices emphasize automated testing pipelines with tools like Jenkins or GitHub Actions for rapid iteration and rollback capabilities.[83] Iteration follows deployment through ongoing monitoring and refinement to counteract model degradation from data drift—shifts in input distributions—or concept drift—changes in underlying relationships.[84] Key metrics include prediction accuracy, latency, and custom business KPIs, tracked via platforms like Datadog, which detect anomalies in real-time production data.[85] When performance thresholds are breached, automated retraining pipelines ingest fresh data to update models; for example, Amazon SageMaker Pipelines trigger retraining upon drift detection, reducing manual intervention and maintaining efficacy over time.[86] Retraining frequency varies by domain, with empirical evidence indicating quarterly updates suffice for stable environments but daily cycles are necessary for volatile data streams, as unchecked staleness can erode value by up to 20% annually in predictive tasks.[87] Continuous testing during iteration validates updates against holdout sets, ensuring causal links between data changes and outcomes remain robust, while versioning tools preserve auditability.[88] Surveys underscore that without systematic iteration, 80-90% of models fail to deliver sustained impact, underscoring the need for feedback loops integrating operational metrics back into development.[81]Technologies and Infrastructure
Programming Languages and Libraries
Python dominates data science workflows due to its readability, extensive ecosystem, and integration with machine learning frameworks, holding the top position in IEEE Spectrum's 2025 ranking of programming languages weighted for technical professionals.[89] Its versatility supports tasks from data manipulation to deployment, with adoption rates exceeding 80% among data scientists in surveys like Flatiron School's 2025 analysis.[90] Key Python libraries include:- NumPy: Provides efficient multidimensional array operations and mathematical functions, forming the foundation for numerical computing in data science.[91]
- Pandas: Enables data frame-based manipulation, cleaning, and analysis, handling structured data akin to spreadsheet operations but at scale.[92]
- Scikit-learn: Offers implementations for classical machine learning algorithms, including classification, regression, and clustering, remaining the most used framework per JetBrains' 2024 State of Data Science report.[93]
- Matplotlib and Seaborn: Facilitate statistical visualizations, with Matplotlib providing customizable plotting and Seaborn building on it for higher-level declarative graphics.[91]
- TensorFlow and PyTorch: Support deep learning model training and inference, with PyTorch gaining traction for research due to dynamic computation graphs.[94]
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