[R-meta] Moderator level getting removed from model

Shannon Duncan shannon at decisionsciences.columbia.edu
Mon Feb 12 18:23:29 CET 2018

```Hello,

I have a question that I can't seem to find an answer to, hoping someone
here can help me out. We are running the following model:

resalt <- metafor::rma(cohens_d, variance, mods = ~ factor(tridiff) *
Provides.Decision.Aids, test = "t", data = choiceaccdata)

resalt

## tau^2 (estimated amount of residual heterogeneity):     0.0574 (SE =
0.0175)
## tau (square root of estimated tau^2 value):             0.2395
## I^2 (residual heterogeneity / unaccounted variability): 67.78%
## H^2 (unaccounted variability / sampling variability):   3.10
## R^2 (amount of heterogeneity accounted for):            39.40%
##
## Test for Residual Heterogeneity:
## QE(df = 72) = 195.8927, p-val < .0001
##
## Test of Moderators (coefficient(s) 2:5):
## F(df1 = 4, df2 = 72) = 6.8504, p-val < .0001
##
## Model Results:
##
##                                          estimate      se     tval
pval
## intrcpt                                   -0.2234  0.0527  -4.2434
<.0001
## factor(tridiff)2                          -0.1642  0.1415  -1.1609
0.2495
## factor(tridiff)3                          -0.4823  0.1523  -3.1656
0.0023
## Provides.Decision.Aids                     0.2183  0.0996   2.1910
0.0317
## factor(tridiff)3:Provides.Decision.Aids    0.6595  0.2218   2.9736
0.0040
##                                            ci.lb    ci.ub
## intrcpt                                  -0.3284  -0.1185  ***
## factor(tridiff)2                         -0.4462   0.1178
## factor(tridiff)3                         -0.7860  -0.1786   **
## Provides.Decision.Aids                    0.0197   0.4169    *
## factor(tridiff)3:Provides.Decision.Aids   0.2174   1.1017   **

As you can see, it's not showing the second level of the factor  tridiff
(tridiff2) interacting with Decision Aids. I realise this is probably due
to redundancy or something of that sort, but we would like to see it
printed out. Is that at all possible?

Thank you for your time and any insight you can provide,
Shannon

[[alternative HTML version deleted]]

```