I’m running a research in which there are 2 groups - intervention group (will go through a 14 day treatment) & control group (will go through a placebo intervention) - comprised of heterosexual couples in a romantic relationship. Each partner will complete the same series of relationship related questionnaires (relationship satisfaction, sexual functioning, general wellbeing etc.) three time (before the interventions, after them and one month follow up).
(1) Compared to the pre-treatment evaluation, couples in the intervention group will show fewer symptoms immediately after completing the intervention and one month following that.
(2) Couples in the intervention group will show fewer symptoms compared to the couples in the control group, immediately after completing the interventions and one month following that.
In addition, I might want to compare the effect of treatment on males and females.
Someone said I should create one score for each couple on the dependent variables (questionnaires) by averaging the responses of both partners, but I’m not sure if it’s the right way to go.
What do you think is the best analysis for this study design?
I would appreciate any help.