Ainsworth's strange situation is a useful research method which provides a lot of information about attachment. It had standardised procedure of fixed timings for each stage and what occurred in each stage, making it easy to replicate which led to a rapid increase in the amount of research carried out into attachments variations, within and between cultures. This increases the validity of the findings as supporting replications can be done with similar results each time. However, as it was a controlled observation there may have been researcher bias.