Table 1.

Descriptive Characteristics of Full and Best-Evidence Samples.

Characteristic	Full sample			Best-evidence sample
	$(k=50)$, $(n=140)$			$(k=17)$, $(n=36)$
	$n$	%	$M\left(SD\right)$	$n$	%	$M\left(SD\right)$
Peer-reviewed publication	62	44		26	72
Sample restrictions
Posttransfer	84	52		0	0
Different cohort definitions	26	18		0	0
Baccalaureate aspirants	27	19		12	33
Identification strategy
Mean comparison	76	54		0	0
Regression	39	28		19	53
Exploit exogenous variation	9	6		7	19
Propensity score matching	18	13		10	28
Statistical controls
Background characteristics	60	42		36	100
Aspirations	33	23		21	58
Enrollment pattern	23	16		10	28
Data characteristics
Year began collegea			1990.8 (11.44)			1991.17 (10.94)
Follow-up perioda			6.68 (1.91)			7.31 (2.04)
Control-group graduation ratea			.64 (0.17)			.6 (0.14)
Effect size			−.16 (0.18)			−.23 (0.1)

Note: $k$ = number of data sources; $n$ = number of effect sizes.

^aContinuous variable.