Editor’s note: Joanna Jones is the CEO and founder of InterQ and co-founder of InterQ Learning Labs. This is an edited version of an article that originally appeared under the title “How to write a screener for recruiting market research studies.”

If you work in market research, recruiting the right participants for your study is an essential part of the job. This article will focus on how to write a screener for qualitative research studies. A screener is the document you send out (typically in the form of an online survey) for potential participants to fill out. They are essential in ensuring that the candidates you’re targeting have the correct demographic and psychographic qualities for your segments. In qualitative research, this is particularly essential, as qualitative employs smaller sample sizes, with more homogenous targets.

In quantitative surveys, screeners are also essential, but they’re typically part of the initial survey questions. However, in qualitative research, screeners are used before participants are interviewed – whether the ultimate study design is a focus group, in-depth interview, UX research or mobile or in-person ethnographies. Here are some guidelines for putting together an effective qualitative research screener.

If you’ve written discussion guides before for qualitative research, you know that the rule of thumb is general to specific. You want participants to define the categories before you do. I like to visualize an upside-down triangle, with general topics before specific.

In recruiting screeners, however, the opposite is true. You want to start off with the specific categories first, or, in other words, the questions that are must-haves for the participant to have to qualify. Put your specific questions first to save participants time – you want to qualify or disqualify people early on, versus making them fill out a long screener, only to put your must-have...