TABLE 4.

Initial balance check and balance check after PSM of online versus face-to-face groups on selected covariates

Covariate	Initial balance				After balance
	Mean diffa	SE	Std mean diff	Var ratio	Mean diffa	SE	Std mean diff	Var ratio
Mentee’s career stage (faculty)	−0.240***	0.040	−0.620	0.358	−0.132***	0.040	−0.318	0.713
Mentee’s career stage (graduate)	−0.017	0.044	−0.036	0.988	−0.121***	0.044	−0.250	0.964
Mentee’s career stage (undergraduate)	0.526***	0.041	1.286	0.458	−0.005	0.045	−0.009	1.145
Mentee’s career stage (none)	−0.038**	0.017	−0.241	0.155	−0.006	0.017	−0.030	0.982
Title	−0.225*	0.119	−0.176	0.781	−0.269**	0.114	−0.226	0.615
Mentor’s previous mentoring experience	−0.375***	0.057	−0.630	0.635	0.165***	0.062	0.228	1.291
Mentor’s years of experience	1.868***	0.690	0.245	0.954	−0.507	0.667	−0.068	0.951
Mentor’s years of experience (NA)b	−0.283***	0.041	−0.710	0.358	0.170***	0.043	0.338	1.323
Sex	−0.260**	0.101	−0.260	0.433	0.286***	0.101	0.245	1.167
Race/ethnicity	0.509***	0.057	0.960	0.178	0.076	0.061	0.105	1.311

^aMean difference refers to the difference in means of online and face-to-face groups (face-to-face is the reference group).

^bThis binary variable was generated to address the missing values of a mentor’s years of experience, with 1 indicating the missingness of years of experience and 0 representing that years of experience is not missing. Therefore, the mean of this variable refers to the percent of missing values.

*p < 0.1.

**p < 0.05.

***p < 0.01.