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

We can use a commercial panel by itself, or as an addition to other recruitment channels (to help fill out our 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).

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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 notified about specific cases), but remember that regardless of the methods we use to recruit, we will still need to watch for garbage responses when we analyze the data later. (See Cleaning the data in Chapter 12.)

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

• Does the panel cover our region?
  If we want participants from a particular province, state, or country, we need to check with the vendor to make sure they have adequate numbers in that region. International 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 we want?
  Most commercial recruitment panels consist of consumers. This works well if we’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. We may need to find a more suitable source of participants - see Other ways to recruit later in this chapter.
  
  
• Will we need to do additional screening of your own?
  While the criteria we supply to the panel will net us a subset of their members, this may not be specific enough for our study. For example, we may have asked the panel for women aged 40-60 who shop online at least once a month, but we’re really only interested in those who have returned at least one item that they bought online.
  Once we go beyond the criteria that the panel offers, we need to do additional screening – see Screening for specific participants later in this chapter.

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Next: Using integrated recruitment tools