Note(s): This table presents the first-stage estimation results of the two-stage Heckman selection model (Eq. (1)). The dependent variable is IDTPA, an indicator variable equal to one if a company engages in ID-TPA projects in the current year. Columns (1)–(4) report the results when the test variables for hypotheses H1–H4 are individually added, respectively; while column (5) reports the results when all test variables are added simultaneously. Numbers in parentheses are z-statistics. ***/**/*: significant at the 1%/5%/10% level (two-tailed), respectively. Please refer to Appendix 2 for variable definitions