Dear all users,
I am interested to examine the effect of emotional IPV on ANC visits differ by women educational status or not.

Outcome variable: (adequate ANC service (1) or inadequate ANC service (0))
Main exposures: spousal emotional IPV (Yes/No or 1/0)
Moderators: (Education status) - Lower education (1) & Higher education (2).
Hypothesis 1:
The effect of emotional IPV on adequate ANC services will be moderated by education and wealth.

I have fitted the model using the following commands:
xtmelogit anc_adequacy i.emotional_viol1##1.educ_mom i.age_catgorey i.husband_educ i.wealth_hh i.mediae_expo i.dma i.birth_order i.V102 i.contextual_regions || psu :,or nolog
Output:
Mixed-effects logistic regression Number of obs = 2,863
Group variable: psu Number of groups = 618
Obs per group:
min = 1
avg = 4.6
max = 12
Integration points = 7 Wald chi2(17) = 263.01
Log likelihood = -1571.0285 Prob > chi2 = 0.0000
------------------------------------------------------------------------------------------------
anc_adequacy | Odds Ratio Std. Err. z P>|z| [95% Conf. Interval]
-------------------------------+----------------------------------------------------------------
emotional_viol1 |
Yes | 1.154874 .4641096 0.36 0.720 .525366 2.538676
|
educ_mom |
Primary or no education | .6540172 .13108 -2.12 0.034 .4415592 .9687003
|
emotional_viol1#educ_mom |
Yes#Primary or no education | .6461428 .2718937 -1.04 0.299 .2832351 1.474042

Note: results of all other covariates excluded

Therefore, there is no main effect of emotional violence (p = 0.720) on ANC and statistical insignificant interaction on this model between emotional IPV and low education (p = 0.299), while adjusted for all covariate. But using these same variables the model fitted without interaction terms found that the effect of emotional IPV (p= 0.021) on ANC visits depends on women’s low education. Here, the commands and the finding using stat 16:
. xtmelogit anc_adequacy emotional_viol1 i.age_catgorey i.husband_educ i.wealth_hh i.mediae_expo i.birth_order i.dma i.V102 i.contextu al_regions if educ_mom==1 || psu :,or nolog
d-effects logistic regression Number of obs = 2,548
Group variable: psu Number of groups = 580

Obs per group:
min = 1
avg = 4.4
max = 12

Integration points = 7 Wald chi2(15) = 160.53
Log likelihood = -1384.4623 Prob > chi2 = 0.0000

------------------------------------------------------------------------------------------------
anc_adequacy | Odds Ratio Std. Err. z P>|z| [95% Conf. Interval]
-------------------------------+----------------------------------------------------------------
emotional_viol1 | .7387078 .0969917 -2.31 0.021 .571098 .9555089
|
age_catgorey |
25 – 34 | 1.433873 .2368658 2.18 0.029 1.037285 1.982089
35 – 49 | 1.446263 .3013516 1.77 0.077 .9613604 2.175748

My question is why these two models finding vary? Is there any mistakes I have made in the commands to fit the models? If not, both the main effects and interaction terms are insignificant, why the stratified analyses become sig. for the main effect emotional IPV (p = 0.021)? Why the number of participants are different (2863 vs. 2548) in the two models?
Thank you so much in advance for your quick responses.