A projector-based approach to quantifying total and excess uncertainties for sketched linear regression
A projector-based approach to quantifying total and excess uncertainties for sketched linear regression
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DOI:
10.1093/imaiai/iaab016
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发表时间:
2021-08-11
影响因子:
1.6
通讯作者:
Ipsen, Ilse C. F.
中科院分区:
文献类型:
--
作者:
Chi, Jocelyn T.;Ipsen, Ilse C. F.
Linear regression is a classic method of data analysis. In recent years, sketching-a method of dimension reduction using random sampling, random projections or both-has gained popularity as an effective computational approximation when the number of observations greatly exceeds the number of variables. In this paper, we address the following question: how does sketching affect the statistical properties of the solution and key quantities derived from it? To answer this question, we present a projector-based approach to sketched linear regression that is exact and that requires minimal assumptions on the sketching matrix. Therefore, downstream analyses hold exactly and generally for all sketching schemes. Additionally, a projector-based approach enables derivation of key quantities from classic linear regression that account for the combined model- and algorithm-induced uncertainties. We demonstrate the usefulness of a projector-based approach in quantifying and enabling insight on excess uncertainties and bias-variance decompositions for sketched linear regression. Finally, we demonstrate how the insights from our projector-based analyses can be used to produce practical sketching diagnostics to aid the design of judicious sketching schemes.