Anyone who has done user research is familiar with Murphy's Law  – the participant doesn’t show up on time, the test equipment fails (it was working this morning!) – and the list goes on.

For in-person sessions, the main challenge is getting the right participant in the right room at the right time. Mostly that’s a matter of good recruiting, though life does happen – traffic is heavy, kids get sick, etc.

For online testing, the main things to cover are:

• Piloting your test to shake out mistakes in the tree and the task wording
  
  
• Providing a contact for participants who encounter problems
  
  
• Alerting your support channels that you’re doing a study, in case participants call to check that it’s legitimate.
  
  

For more on handling problems during a test, see Checking for technical problems in Chapter 10 and Monitoring the test's progress in Chapter 11.

Next: Documenting your plan