Archive for the 'sample size' Category

Improving participation rates: research recruitment best practices

May 23, 2009

Those of you out there who’ve tried it know: recruiting research participants is HARD. Here are a few insights from the research to help you with better recuitment.

  1. Personalized contact with respondents, followed by pre-contact and aggressive follow-up phone calls *: Don’t count on a form letter, email or random tweet to do the job. Capitalize on your personal relationship with that person. If you don’t have a personal relationship, ensure that you use the person’s name, and for God’s sake, spell it correctly!

    Once you’ve made initial contact, you are not done. Not by a long shot. Make sure you speak to the person (you can do this through IM or email if you’d like) to give them more information. They’re now interested. Don’t stop! One more step!

    Follow up 1 week after initial contact. Assuage any fears they may have. Answer any questions honestly. And above all, be available for more information.

  2. External researchers with social capital are best**: University-based researchers have been shown to have the best participation rates, but you don’t have to be a professor.  Researcher Sister Marie Augusta Neal of Emmanuel College achieved a near perfect response rate because of her close ties to the respondents and their communities. The lesson here is, if you hire a consultant, make sure they’re trusted. Even better if they personally know the people to be recruited.
  3. Monetary incentives have no effect, unless money is offered “no strings attached”***: Little known fact: the best way to use a monetary incentive is to offer it, up front, with absolutely no strings attached. The “free” money makes people feel more indebted socially. Evidence of this effect can be found in the book Freakonomics. Researchers found that daycare centres that levied late penalties on tardy parents actually had more of a late-pickup problem than those that levied no fine. Why? Because the parents reduced their relationship to the daycare as a mere transaction. Use the “gift economy” approach and ensure a feeling of indebtedness. My personal favourite is a coupon for a single iTunes song at $.99. It is cheap but appears to have great value. Offer it, up front, and then ask for participation

*  Cook, C., F. Heath, and R. Thompson. 2000. “A Meta-analysis of Response Rates in Web or Internet-based Surveys.” Educational and Psychological Measurement 60:821-836.

** Rogelberg, S., A. Luong, M. Sederburg, and D. Cristol. 2000. “Employee Attitude Surveys: Examining the Attitudes of Noncompliant Employees.” Journal of Applied Psychology 85:284-293.

***Hager, M., S. Wilson, T. Pollak, and P. Rooney. 2003. “Response Rates for Mail Surveys of Nonprofit Organizations: A Review and Empirical Test.” Nonprofit and Voluntary Sector Quarterly 32:252-267. Singer, E. (2006) Introduction: Nonresponse Bias in Household Surveys. Public Opinion Quarterly, 70, 637-645

Qualitative versus quantitative research

August 16, 2007

Many designers are self-taught, intuitive consumers of research who can translate insights into great designs. But few are trained in the arcane art of research itself. For that reason, many designers don’t know the finer differences between qual and quant research and end up using their respective results inappropriately.

Quantitative research is based on the assumption that random events are predictable, and if you compare your results to pure random results, you can discern distinctive, meaningful patterns about the social world.

Random events are relatively MORE predictable if you have more of them. Imagine if you flipped a coin 20 times. How many heads would you get? Now if you flipped it 20,000 times? You’re more likely to get an even 50/50 split — which is what most people would predict. If you got a 65/35 split with 2o flips, okay, could happen. But with 20,000 flips? No way. Something else is going on.

Translate that to design research by looking at gender, for example. Let’s say you have 20 people, 10 men and 10 women. 65% of the women choose one design, while only 35% of the men do. Is this a meaningful pattern? Impossible to say — you only have 20 people. Now if you had 200 people (100 men and 100 women) and 65 of the women chose one design, chances are you have a meaningful pattern.

This is why sample size matters in quantitative research. But, little known fact, sample size is COMPLETELY IRRELEVANT in qualitative research. Why?

Qualitative research assumes that people have meaningful experiences that can be interpreted. Notice how there’s nothing in there about “prediction” or “randomness.” People have experiences. Researchers discern what these experiences signify. That’s it. Sample size is not only irrelevant, it actually gets in the way of important insight.

Consider the case study, for example. Few people would say case studies are useless. We can learn a great deal about a single design case, where it went wrong and where it went right. The problem comes when you try to predict future events based on this single event.

If you abandon the need for prediction, then sample size never matters. You can always derive insight about design problems from even a single case. Designers that attempt to predict “success” of a single design change, for example, should test that change, repeatedly, with a probability sample.