Figure 4.1 depicts the distribution of reported outcomes across treat-ments. The dashed line represents the expected frequency if every par-ticipant reported the true outcome of the four coin ips. The main results are also summarized in Table 4.2.
Observation 1: In all treatments, the overall distribution of re-ported outcomes is signi cantly shifted to the right of the truthful distribution.
Figure 4.1 reveals that in all treatments the observed distributions of reported outcomes dier from the theoretical benchmark. The most fre-quent outcome reported is 3, i.e., a majority of subjects refrains from reporting the payo-maximizing outcome of 4. The distribution of re-ported outcomes in all four treatments is signi cantly dierent from the truthful distribution (Kolmogorov-Smirnov tests, all four p<0.01). This
nding is also con rmed by binomial tests. In the treatments Phone, PC-Lab and PC-Online, the frequencies of reporting 1 or 2 are signi cantly below the expected distribution, whereas the frequencies of reported out-comes of 3 and 4 are signi cantly above the honest distribution (see Table
Table 4.2: Overview of results
Treatment n r¯i Belief ¯ri Reported outcome ri(rel. frequencies)
0 1 2 3 4
F-t-F 60 2.73 2.85 0.02 0.02−−− 0.3 0.55+++ 0.12
Phone 60 2.75 2.89 0.02 0.07−− 0.22−−− 0.55+++ 0.15++
PC-Lab 60 2.71 2.80 0.00− 0.12−− 0.23−− 0.47+++ 0.18+++
PC-Online 66 2.86 2.86 0.00−− 0.08−−− 0.24−− 0.42++ 0.26+++
Honest distribution 2 0.06 0.25 0.38 0.25 0.06
JT test p=0.097 p=0.065 p=0.729 p=0.051 p=0.017
Notes: n stands for the number of observations. ¯riis the average reported output. Plus and mi-nus signs display the signi cance of a one-sided binomial test indicating that the observed relative frequency is smaller (larger) than the expected frequency −(+)=10-%-level, −−(++)=5-%-level,
−−−(+++)=1-%-level. JT test stands for applying a Jonckheere-Terpstra test for ordered alterna-tives (p-values refer to one-sided tests).
4.2 for details). In the F-t-F treatment, the reported frequencies for out-comes 1 and 3 are also statistically distinguishable from the expected frequencies. In this treatment, however, the frequencies of reporting 0, 2 and 4 are statistically indistinguishable from the truthful distribution.
The average reported outcomes are not statistically dierent between the treatments.
Observation 2: The fraction of subjects reporting the outcome of 4 increases the more distant the means of communication is.
Focusing only on the reported outcome of 4, Figure 1 displays dif-ferences in reporting this outcome across treatments. According to a Jonckheere-Terpstra test for ordered alternatives, reporting the highest possible outcome is more likely as the anonymity of the communication medium increases (p=0.017, one-sided).
Pairwise comparisons of the fraction of subjects reporting the outcome 4 yields a signi cant dierence between treatments F-t-F and PC-Online, i.e., 12% in F-t-F and 26% in PC-Online (p=0.04, χ2-test, two-sided).
No statistical dierences exist for other pairwise treatment comparisons (see also Table A4.1 in the appendix for probit regressions on reporting the outcome 4).
In treatment PC-Online, 30% of the women report the outcome 4,
whereas in the other treatments only 10% or less of the women report the highest possible outcome (see also Figure A4.1 and A4.2 in the ap-pendix). Pairwise χ2-tests of the fractions of women reporting the out-come 4 yield signi cant dierences between treatment PC-Online and the other treatments (p=0.053 between PC-Online and F-t-F as well as Phone, and p=0.02 between PC-Online and PC-Lab, two-sided). Com-parisons between reporting behavior of men and women reveal no statis-tical dierences.13
Observation 3: Partial lying is more pronounced in treatments where the means of communication is less anonymous.
Subjects across treatments most frequently report outcome 3. Accord-ing to a Jonckheere-Terpstra-test, reportAccord-ing this outcome is more likely as the anonymity of the communication channel decreases (p=0.051, one-sided). Pairwise treatment comparisons show no statistical dierences.
Observation 4: Being high in Conformity values has a negative eect on reporting high outcomes.
Ordered logistic regressions of the reported outcomes with several co-variates were run that are displayed in Table 4.3. Model (1), dummy vari-ables of the treatments were included, which have no signi cant eect on reported outcomes. Moreover, neither age nor gender have a signi cant eect on reporting outcomes (model 2). Model (3) includes a dummy for Conformity values from the value theory of Schwartz (1992). Subjects who score higher in Conformity report signi cantly smaller outcomes.14 According to the de nition of the conformity trait, people who score highly in Conformity values avoid actions and intentions that could up-set or harm others and violate social norms and expectations (Schwartz, 1992). Other characteristics like religiousness, income, risk attitudes and Machiavellianism are not signi cantly associated with the reported out-come (see Table A4.2 in the appendix).
13In contrast, Dreber and Johannesson (2008), for example, nd that men lie more often compared to women.
14According to Schwartz's model (1992), people distinguish between at least ten basic values. These values are Universalism, Benevolence, Tradition, Conformity, Secu-rity, Power, Achievement, Hedonism, Stimulation, and Self-Direction (Schwartz, 1992).
Table 4.3: Regression analysis of reported outcomes
Dependent variable:
Number of reported tails (1) (2) (3) (4) (5)
Phone 0.102 0.072 0.057 0.103 0.037
(0.303) (0.307) (0.312) (0.345) (0.349)
PC-Lab 0.014 -0.006 -0.001 0.020 -0.015
(0.330) (0.332) (0.349) (0.349) (0.354)
PC-Online 0.335 0.337 0.232 0.108 0.245
(0.333) (0.337) (0.341) (0.347) (0.359)
Age -0.034 -0.041
(0.031) (0.033)
Gender (1 if female) -0.083 -0.074
(0.243) (0.252)
Conformity -1.207** -1.245**
(0.415) (0.485)
Belief about other subjects 4.927*** 4.676***
(0.757) (0.766)
Observations 246 246 246 242 242
Pseudo R-squared 0.002 0.004 0.014 0.084 0.087
Notes: Ordered logit estimates. Robust standard errors in parentheses. Reference group is treatment F-t-F. The number of observations diers because of missing values. Phone, PC-Lab, and PC-Online represent dummy variables for the respective treatments. "Belief about other subjects" is the belief about the share of other subjects who report to have ipped more tails than they actually did and who then report the outcome 4 tails (see section 4.4.2 for details). Signi cances at the 1, 5, and 10 percent level are denoted by ***, **, and *, respectively.