Table 1.

Facebook analytics terms and measures.

	Definition
Impressions	The number of times the advertisement appeared in a news feed
Reach	The number of times the advertisement was seen at least once by a user
Click	An interaction with the advertisement
Cost per click	The cost of the ad divided by the number of times the ad was clicked
Conversion rate	The number of people who click on the ad and then become participants (eligibility is not excluded)
Cost per participant	The cost of advertising divided by the eligible recruited participants
Frequency	Average number of times each person saw the ad
Result rate	The number of clicks divided by the number of impressions