Table 4.
Factor loadings, discrimination, threshold, and difficulty parameters for IM for dichotomous and polytomous scoring.
| Items | Dichotomous scoring | Polytomous scoring | ||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Factor loading | a1 | a2 | b | Factor loading | a1 | a2 | Difficulty (b) | |||||||||
| 1 | 2 | 1 | 2 | 1 | 2 | 3 | 4 | 5 | 6 | |||||||
| Impression management | ||||||||||||||||
| 21 | I sometimes tell lies if I have to. | .69 | 1.61 | 0.94 | .64 | 1.41 | −2.30 | −1.23 | −0.28 | 0.46 | 0.99 | 2.24 | ||||
| 23 | There have been occasions when I have taken advantage of someone. | .69 | 1.61 | 0.46 | .53 | 1.06 | −4.16 | −3.17 | −2.03 | −1.19 | −0.56 | 0.86 | ||||
| 25 | I sometimes try to get even rather than forgive and forget. | .60 | 1.27 | −0.11 | .49 | 0.94 | −4.55 | −2.80 | −1.74 | −0.81 | −0.12 | 1.25 | ||||
| 27 | I have said something bad about a friend behind his/her back. | .52 | 1.05 | −1.50 | .47 | 0.91 | −2.34 | −1.13 | 0.06 | 1.04 | 1.68 | 3.07 | ||||
| 29 | I have received too much change from a salesperson without telling him or her. | .51 | 1.07 | 1.10 | .50 | 0.99 | −1.05 | −0.22 | 0.48 | 0.90 | 1.18 | 1.77 | ||||
| 31 | When I was young I sometimes stole things. | .44 | 0.83 | −0.16 | .47 | 0.91 | −1.63 | −0.91 | −0.42 | −0.05 | 0.21 | 0.87 | ||||
| 33 | I sometimes drive faster than the speed limit. | .21 | 0.37 | 5.41 | .32 | 0.57 | −0.53 | 0.81 | 2.12 | 3.02 | 3.64 | 4.47 | ||||
| 35 | I have done things that I do not tell other people about. | .53 | 1.05 | −1.29 | .58 | 1.21 | −1.24 | −0.25 | 0.31 | 0.85 | 1.19 | 1.91 | ||||
| 37 | I have taken sick-leave from work or school even though I wasn’t really sick. | .43 | 0.81 | 1.09 | .52 | 1.05 | −0.86 | −0.10 | 0.36 | 0.75 | 0.94 | 1.46 | ||||
| 39 | I have some pretty awful habits. | .47 | 0.90 | −1.81 | .45 | 0.87 | −2.27 | −1.00 | 0.13 | 1.20 | 1.87 | 3.47 | ||||
| 22 | I never cover up my mistakes. | .51 | 1.01 | 2.03 | .34 | 0.62 | −4.66 | −1.89 | 0.06 | 1.72 | 2.98 | 5.16 | ||||
| 24 | I never swear. | .35 | 0.63 | 4.22 | .50 | 0.99 | 0.18 | 1.11 | 1.74 | 2.32 | 2.89 | 4.43 | ||||
| 26 | I always obey laws, even if I’m unlikely to get caught. | .46 | 0.88 | 1.05 | .49 | 0.95 | −2.74 | −1.28 | −0.39 | 0.24 | 0.97 | 2.73 | ||||
| 28 | When I hear people talking privately, I avoid listening. | .52 | 1.03 | 1.72 | .47 | 0.90 | −2.48 | −0.77 | 0.16 | 1.15 | 1.87 | 3.24 | ||||
| 30 | I always declare everything at customs. | .31 | 0.55 | 0.04 | .26 | 0.46 | −4.15 | −2.86 | −2.13 | −0.82 | 0.10 | 1.48 | ||||
| 32 | I have never dropped litter on the street. | .52 | 1.03 | 0.20 | .53 | 1.06 | −0.30 | 0.56 | 1.09 | 1.54 | 1.94 | 2.96 | ||||
| 34 | I never read sexy books or magazines. | .40 | 0.74 | 0.76 | .35 | 0.63 | −2.09 | −0.91 | −0.25 | 0.55 | 0.88 | 2.04 | ||||
| 36 | I never take things that do not belong to me. | .63 | 1.39 | −0.24 | .45 | 0.86 | −3.16 | −2.17 | −1.42 | −0.77 | −0.34 | 0.77 | ||||
| 38 | I have never damaged a library book or […] without reporting it. | .60 | 1.27 | −0.33 | .40 | 0.75 | −2.64 | −1.97 | −1.43 | −1.06 | −0.48 | 0.47 | ||||
| 40 | I do not gossip about other people’s business. | .44 | 0.83 | 1.93 | .38 | 0.70 | −3.52 | −1.35 | 0.02 | 1.35 | 2.24 | 4.62 | ||||
a is the discrimination parameter (or slope). For polytomous scoring, given that each item has 7 item categories, there are six thresholds (i.e., difficulty parameter, b) creating these seven categories. The mirt package in R only provides estimates for intercepts which can be transformed into threshold values for each item using the following formula (−d/a), where d is the intercept value for the corresponding response category and a is the slope for the item. The intercept together with confidence intervals can be found in Supplementary material S1. Darker notation indicate greater factor loadings (< .40; .40–.55; ≥ .55) and discrimination parameters (<0.65; 0.65–1.34; > 1.34); Items 31, 36, 39 where indicated as misfitting (sign. S-X2 statistics) for polytomous scoring.