# Most-cited Mathematics papers of 2022, with free PDFs

The 25 most-cited Mathematics research papers published in 2022, ranked by citations in OpenAlex, with their original abstracts and free PDFs where available.

1. [How much should we trust staggered difference-in-differences estimates?](https://nerdi.pages.dev/paper/W4283387379) · 3,250 citations
2. [Global impact of the first year of COVID-19 vaccination: a mathematical modelling study](https://nerdi.pages.dev/paper/W4283395367) · 1,782 citations
3. [Estimating excess mortality due to the COVID-19 pandemic: a systematic analysis of COVID-19-related mortality, 2020–21](https://nerdi.pages.dev/paper/W4220867566) · 1,732 citations
4. [Receiver operating characteristic curve: overview and practical use for clinicians](https://nerdi.pages.dev/paper/W4205134630) · 1,485 citations
5. [When Should You Adjust Standard Errors for Clustering?](https://nerdi.pages.dev/paper/W2962975811) · 1,471 citations · Free PDF
6. [Generalizing hierarchical and variation partitioning in multiple regression and canonical analyses using the rdacca.hp R package](https://nerdi.pages.dev/paper/W4205237613) · 1,268 citations · Free PDF
7. [The WHO estimates of excess mortality associated with the COVID-19 pandemic](https://nerdi.pages.dev/paper/W4311472757) · 1,068 citations · Free PDF
8. [Target Trial Emulation](https://nerdi.pages.dev/paper/W4311204752) · 993 citations
9. [Optimal ratio for data splitting](https://nerdi.pages.dev/paper/W4226017353) · 783 citations · Free PDF
10. [Pretest with Caution: Event-Study Estimates after Testing for Parallel Trends](https://nerdi.pages.dev/paper/W4293761886) · 760 citations
11. [A Crash Course in Good and Bad Controls](https://nerdi.pages.dev/paper/W4288048568) · 619 citations
12. [Mitigating the Multicollinearity Problem and Its Machine Learning Approach: A Review](https://nerdi.pages.dev/paper/W4223552619) · 613 citations · Free PDF
13. [A Review of Wavelet Analysis and Its Applications: Challenges and Opportunities](https://nerdi.pages.dev/paper/W4285065952) · 581 citations
14. [glmm.hp: an R package for computing individual effect of predictors in generalized linear mixed models](https://nerdi.pages.dev/paper/W4309908755) · 551 citations
15. [Two-way fixed effects and differences-in-differences with heterogeneous treatment effects: a survey](https://nerdi.pages.dev/paper/W4293198822) · 535 citations
16. [Interpreting area under the receiver operating characteristic curve](https://nerdi.pages.dev/paper/W4306722800) · 497 citations · Free PDF
17. [Real-world data: a brief review of the methods, applications, challenges and opportunities](https://nerdi.pages.dev/paper/W4308292299) · 490 citations · Free PDF
18. [Cross validation for model selection: A review with examples from ecology](https://nerdi.pages.dev/paper/W4309048734) · 464 citations · Free PDF
19. [Sample size calculation for prevalence studies using Scalex and ScalaR calculators](https://nerdi.pages.dev/paper/W4288758543) · 437 citations · Free PDF
20. [Pandemic preparedness and COVID-19: an exploratory analysis of infection and fatality rates, and contextual factors associated with preparedness in 177 countries, from Jan 1, 2020, to Sept 30, 2021](https://nerdi.pages.dev/paper/W4210677265) · 427 citations
21. [The triple difference estimator](https://nerdi.pages.dev/paper/W3020461982) · 423 citations
22. [Sample size determination: A practical guide for health researchers](https://nerdi.pages.dev/paper/W4311479404) · 403 citations
23. [Handling missing data in clinical research](https://nerdi.pages.dev/paper/W4296631245) · 393 citations
24. [A Practical Guide to Counterfactual Estimators for Causal Inference with Time‐Series Cross‐Sectional Data](https://nerdi.pages.dev/paper/W3182501931) · 388 citations · Free PDF
25. [Can Cross-Sectional Studies Contribute to Causal Inference? It Depends](https://nerdi.pages.dev/paper/W4214755521) · 360 citations

Canonical page: https://nerdi.pages.dev/papers/mathematics/most-cited-2022