Q1: How can I use BayesiaLab to combine respondent-level data from two different surveys? These two surveys have different sample sizes only a few variables in common.
Q2: What if I want to use the two data sets together to find relationship between the different variables from different studies...is it possible?
When you have a Hub, i.e. a set of variables that are common in the different studies, you can merge the two data sets into a single file and define Filtered States for those values that do not exist. You can mark these fields with "*" or "FV" in your dataset to indicate that a question is not applicable for the study. In the first step of the Data Import Wizard you can set the code for Filtered Values.
It is not possible to find relationship between variables that have not been measured together when you do not have a Hub, i.e. without any variable in common.
This is only with such a hub that you may find (indirect) probabilistic relations between variables coming from different studies.
When you do not have a hub, you can build one by inducing a respondent segmentation. Based on some characteristics of the respondents, you can use BayesiaLab:
- for creating a typology, and then
- for asking the most informative questions to predict the cluster in which the respondent belong (e.g. with the Adaptive Questionnaire).
Doing this pre-work for each survey allows you to have at least one variable in your hub.