Table 3.
Moderated-Mediation Model of the Effect of Choice Set Size on Enrollment Likelihood
| Numeracy as the Moderator | ||||||||
| Numeracy = 0 | Numeracy = 1 | Numeracy = 2 | Numeracy = 3 | |||||
| Model 1: Costs as the Mediator | (n=48) | (n=57) | (n=63) | (n=59) | ||||
| Cost measured by choice difficulty | Estimate | 95% BC CI |
Estimate | 95% BC CI |
Estimate | 95% BC CI | Estimate | 95% BC CI |
| Indirect Effect (a*b) | −0.008 | (−0.040–0.005) | −0.012* | (−0.032–−0.001) | −0.016* | (−0.035– −0.004) | −0.021* | (−0.059– −0.003) |
| Choice set size on Enrollment via Costs | ||||||||
| Path (a) | 0.074 | (−0.002–0.152) | 0.084* | (0.034–0.134) | 0.094* | (0.047–0.146) | 0.104* | (0.030–0.184) |
| Choice set size on Costs | ||||||||
| Path (b) | −0.107 | (−0.337–0.120) | −0.138 | (−0.283–0.009) | −0.170* | (−0.295– −0.043) | −0.201* | (−0.402– −0.023) |
| Costs on Enrollment Likelihood | ||||||||
| Direct effect (c'1) | 0.012 | (−0.056–0.083) | 0.003 | (−0.044–0.052) | −0.005 | (−0.055–0.042) | −0.014 | (−0.089–0.055) |
| Choice set size on Enrollment Likelihood | ||||||||
| Numeracy = 0 | Numeracy = 1 | Numeracy = 2 | Numeracy = 3 | |||||
| Model 2: Benefits as the Mediator | (n=47) | (n=57) | (n=62) | (n=59) | ||||
| Benefits measured by similarity to ideal plan | Estimate | 95% BC CI |
Estimate | 95% BC CI |
Estimate | 95% BC CI | Estimate | 95% BC CI |
| Indirect Effect (a*b) | 0.002 | (−0.010–0.031) | 0.005 | (−0.002–0.024) | 0.009* | (0.001–0.023) | 0.012 | (−0.002–0.040) |
| Choice set size on Enrollment via Benefits | ||||||||
| Path (a) | 0.047 | (−0.025–0.116) | 0.047* | (0.002–0.092) | 0.047* | (0.004–0.088) | 0.046 | (−0.024–0.106) |
| Choice set size on Benefits | ||||||||
| Path (b) | 0.042 | (−0.260–0.349) | 0.113 | (−0.074–0.308) | 0.184* | (0.046–0.341) | 0.255* | (0.051–0.483) |
| Benefits on Enrollment Likelihood | ||||||||
| Direct effect (c'1) | 0.009 | (−0.067–0.80) | −0.011 | (−0.062–0.036) | −0.031 | (−0.080–0.011) | −0.051 | (−0.127–0.011) |
| Choice set size on Enrollment Likelihood | ||||||||
Note. Separate models are shown for when costs (benefits) are the mediator. In both cases, the two regressions used were of the following form. In the first regression, y (enrollment likelhood) was regressed on costs (or benefits) (m), the number of plans (x), numeracy (w), costs (benefits) interacted with numeracy (mw), numeracy interacted with the number of plans (wx), and all control variables. In the second regression, the mediator m (costs or benefits) was regressed on the number of plans (x), numeracy (w), numeracy interacted with the number of plans (wx), and all control variables. The control variables used in the regression were age, gender, education, employment status, marital status, race, household income, and the number of drugs taken regularly. Estimates and 95% bias-corrected confidence intervals are shown.