Sometimes you need to dig a bit deeper to get enough participants, or to get a more representative sample of your users (see “Dealing with selection bias” below).
In either case, we can ask ourselves in any of these other methods would work for our particular study:
- Amazon’s Mechanical Turk
This service lets you offer micro-payments to people to do online tasks (in this case, your tree test). But because you’re tapping into a global audience that is keen on earning a series of tiny fees quickly, you need to be extra careful about getting garbage data. - Trade associations and customer groups
Your customers may already have their own groups (online or not), or they may belong to a trade association (e.g. a farming collective or a plumber’s union). Consider asking permission to contact the group’s members for your study, or ask for your invitation to be added to their next newsletter. - Universities and other post-secondary institutions
Students are often willing to participate in a study, both for the experience and for the chance of reward. Ask permission to post a online ad or paper bulletin. - Targeted publications and forums
There are message boards and online forums for every conceivable profession and interest. Post on those that are frequented by the type of user you’re looking for, but be sure to find out if you need permission first to post your request. - Colleagues, friends, and family
Depending on the type of user you’re looking for, you may be able to “shoulder-tap” people you know to participate. If you’re looking for graphic designers, for example, start with a designer you know and ask if they can pass the invitation along to other designers. - SMS (TXT)
If your organization has a list of mobile phone numbers for customers, you could text your study request to these people, using the same short format you may have used for Twitter invitations (see Using social media earlier in this chapter). If they have a smartphone, they can activate the link directly from the TXT message.
We rarely use this channel, however, because (a) it usually costs money to send these messages, (b) the limited length of a plain-text message is harder to work with, and (c) recipients are more likely to consider this to be spam than if you sent the same request as an email.
Next: Dealing with selection bias