Unstructured interviews also lack representativeness – because they are time consuming, it is difficult to get a large enough sample to be representative of large populations. It is difficult to quantify data, compare answers and find stats and trends because the data gained is qualitative.

Are unstructured interviews valid?

Unstructured interviews typically have no set format or predetermined questions and lack a process for scoring candidate responses. ... Unstructured interviews provide low reliability and low validity in predicting job performance and therefore greatly diminishing the likelihood of the right candidates being selected.

Are unstructured interviews formal?

Many people mistakenly assume that an unstructured interview lacks a formal interview style that won't yield consistent answers. While an unstructured interview doesn't require an interviewer to prepare uniform questions in advance along a pre-determined rating scale, there is still a method to it.