Walk the Talk? The Effect of Voting and Excludability in Public Goods Experiments

Table 6

Best results from the genetic algorithm runs for Experiment 2(mixed effects models, maximum likelihood estimation).

	Model 10	Model 11
Dependent variable	Individual contribution
CONSTANT	3.102^∗∗∗	4.149^∗∗∗
ROUND	−0.078^∗∗∗	−0.075^∗∗∗
INDIVIDUAL CONTRIBUTION (−1)^a	0.990^∗∗∗	0.872^∗∗∗
SUCCESS^b(−1) (YES = 1)		1.489^∗∗∗
FEMALE (YES = 1)	−3.076^∗∗∗	−3.279^∗∗∗
FRESHMAN (YES = 1)	−9.241^∗∗∗	−9.239^∗∗∗
GREW UP IN URBAN AREA (YES = 1)	−3.842^∗∗∗	−3.858^∗∗∗
PLAYING XPG FIRST∗ SOCIAL SCIENCES (YES = 1)	0.800^∗∗∗	0.807^∗∗∗
INDIVIDUAL CONTRIBUTION (−1)∗ [SUCCESS (−1) (YES = 1)]	0.223^∗∗∗
INDIVIDUAL CONTRIBUTION (−1)∗ [FEMALE (YES = 1)]	0.127^∗∗∗	0.136^∗∗∗
INDIVIDUAL CONTRIBUTION (−1)∗ EMPATHY	−0.142^∗∗∗	−0.137^∗∗∗
GROUP CONTRIBUTION (−1)∗ EMPATHY	0.016^∗∗∗	0.014^∗∗∗
UNFAIR CONTRIBUTION (−1)∗ [ROUNDS 1–10 (YES = 1)]	−0.605^∗∗∗	−0.583^∗∗∗
[FEMALE (YES = 1)]∗ EMPATHY	0.559^∗∗∗	0.587^∗∗∗
ECONOMICS∗ SENIOR (YES = 1)	−0.436^∗∗∗	−0.431^∗∗∗
SOCIAL SCIENCES∗ GREW UP IN URBAN AREA (YES = 1)	−1.254^∗∗∗	−1.215^∗∗∗
[FRESHMAN (YES = 1)]∗ INTERNAL LOCUS OF CONTROL	2.087^∗∗∗	2.085^∗∗∗
[GREW UP IN URBAN AREA (YES = 1)]∗ PARENT EDUCATION	0.865^∗∗∗	0.864^∗∗∗
INDIVIDUAL EARNINGS (−1) SQUARED	−0.013^∗∗∗
INDIVIDUAL EARNINGS FROM GROUP PROJECT (−1) SQUARED		−0.009^∗∗∗
Akaike Info Criterion	10233.46	10233.67
Bayes Info Criterion	10347.94	10348.15
Log Likelihood	5096.73	5096.84
Number of obs.	2400 (random effect for 24 groups)

aThe sign (−1) next to a variable means that the variable is lagged by one round.
bSUCCESS is a dummy variable with the value of 1 if the group contribution reached the provision point and 0 otherwise.