Stata se statistical software version 16

Data came from the China Health and Retirement Longitudinal Study (2011-2018). This study followed the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) reporting guideline and received institutional review board approval from Peking University. All participants provided written informed consent. We focused on 54 934 middle-aged and older adults with rural household registration, who would be most affected by the integration policy.^{3 (link)} Participants enrolled in the New Rural Cooperative Medical Scheme, Urban Resident Basic Medical Insurance, or Urban and Rural Resident Basic Medical Insurance were then included (50 527 participants). Furthermore, we retained 48 913 respondents without missing values in key covariates, who constituted the final panel.
The independent variable, urban-rural health insurance integration, indicated whether a province implemented the integration policy in the corresponding survey year. On the basis of the staggered implementation of the integration across cities over time, we used a staggered difference-in-differences (DID) model to examine the associations. A multiperiod DID model (event study model) was used to test the parallel trend hypothesis (eAppendix in Supplement 1). Data analysis was performed from September 2022 to February 2023 using Stata SE statistical software version 16 (StataCorp).

This research was classified as not human subjects research by the Beth Israel Deaconess Medical Center institutional review board; thus, informed consent was not needed in accordance with 45 CFR §46. This study follows the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) reporting guideline for cohort studies.
The primary outcome of this study is new daily COVID-19 infections in each county per 100 000 residents. These data came from the New York Times⁴ from January 28, 2021, to May 25, 2021, spanning from 50 days before to 50 days after the tournament. Because social gatherings often become larger later in the tournament, the day of exposure is defined as the date of the latest game a team plays in the tournament.
A difference-in-differences design was used to compare counties with universities competing in March Madness with counties within the same states that were not competing, before and after the tournament (see the eAppendix in the Supplement for details). Analyses were performed in Stata/SE statistical software version 16 (StataCorp). All t tests were 2-tailed, and P < .05 was considered significant.