AO3

• large samples

  P: A strength of combining these results of attachment studies carried out in different countries is that you can end up with a very large sample

  E: For example, in the van Izjerdoorn meta analysis there was a total of nearly 2000 babies and their primary attachment figures

  E: even smaller samples studies had large comparison groups from previous research

  L: this overall sample sizes the strength because large samples increase internal ability by reducing the impact of anomalous results caused by bad methodology or very unusual participants