3. Sample selection and descriptive evidence on reporting trends
To analyze the impact of these regulatory changes on earnings announcement strategies and earnings announcement
reliability, we require data on earnings announcement (Compustat) and audit report (Audit Analytics) dates. Sample
selection is detailed in Table 1. For the calendar years 2000–2005, there are a total of 89,514 firm-year observations in the
Audit Analytics Opinion file. After eliminating duplicate observations, observations not on Compustat (e.g., subsidiaries of
public companies and benefit plans), and observations without earnings announcement dates in the Compustat quarterly
file, we are left with 30,017 firm-year observations. Eliminating observations with extreme audit report lags or filing lags