- Jan 2019
This is one of the most important decisions in an EFA (Thompson, 2004; Warne & Larsen, 2014), and these decisions can make g artificially easier or harder to identify.
Deciding the number of factors to retain can be extremely subjective. But that was why it was so important to pre-register our work. We wanted to choose methods for making this decision before seeing the data so that no one could accuse of us of trying to monkey with the data until we got the results we wanted.
For the sake of transparency, we find it important to explicitly state deviations from our preregistration protocol. First, in our preregistration, we stated that we would search for (cognitive OR intelligence) AND the name of a continent or population. However, searching for a continent was not feasible in finding data sets. We also had difficulty generating a list of population groups (e.g., ethnic groups, tribal groups) that would be useful for our search procedures.
This was my second time I pre-registered the study and the first time my student co-author had. We are still getting the hang of it.