Another source of participants are the many companies that run large online research panels.

You can use a commercial panel by itself, or as an addition to your other recruitment channels (to help fill out your desired numbers).

Users sign up to these panels to earn rewards for doing online studies. When they sign up, the company collects all kinds of information about them – demographics, buying habits, hobbies, and so on. This creates a large database that can be queried for specific types of participants (e.g. women aged 40-60 who shop online at least once a month).

When you (as a researcher) ask the company for participants, you can then specify what kind of people you’re looking for.

While each research panel is different, the process typically goes like this:

• You find an online panel you want to use, based on what kind of users they offer in your region, how much they charge, and whether their participant system can work with your online testing tool. This usually involves studying their website and emailing them specific questions.
  
  
• You set up an agreement with the panel company, specifying how many users you want and how much you will pay for that number of responses.
  
  
• You configure your online study to receive participants from the panel. Usually this involves receiving a “participant identifier” from each incoming participant, then notifying the panel when that participant has completed the study (so the participant can earn their reward from the panel company).
  
  Some tree-testing tools let you configure this as part of your study. Others may require you to do a bit of extra work or ask the vendor to help you set it up, while others may require you to ask each participant for their identifier so you can send it back to the panel company later.
  
  
  

In terms of quality of the results you get, research panels follow the same caveat as most other recruiting methods – you will always get a small percentage of participants who race through the test and give “dummy” answers, just so they can get the reward.

We haven’t found these paid panels to be any worse than other methods in this regard (and, in fact, some of them actively cull members who don’t give a decent effort, if you notify them about specific cases), but remember that regardless of the methods you use to recruit, you will still need to watch for garbage responses when you analyze your data later. (See Cleaning the data in Chapter 12.)

While recruitment panels can work well and can save you a lot of time and effort, there are a few questions you should ask before using them:

• Does the panel cover your region?
  If you want participants from a particular province, state, or country, check with the vendor to make sure they have adequate numbers in that region. Panels usually do a good job of covering North America and western Europe, but may be patchy elsewhere.
  
  
• Is the panel likely to include the types of people you want?
  Most commercial recruitment panels consist of consumers. This works well if you’re targeting a portion of the general public, but it’s harder to use consumer panels for other audiences like business people, farmers, government employees, and so on. You may need to find a more suitable source of participants - see “Other ways to recruit” below.
  
  
• Will you need to do additional screening of your own?
  While the criteria you supply to the panel will net you a subset of their members, this may not be specific enough for your study. For example, you may have asked the panel for women aged 40-60 who shop online at least once a month, but you’re really only interested in those who have returned at least one item that they bought online.
  Once you go beyond the criteria that the panel offers, you may find that you need to do additional screening – see Screening for specific participants later in this chapter.

Next: Using integrated recruitment tools