Complete a set

The compulsion to collect, to be complete, drives people to action. Start them down the path by giving them some initial items in the collection “free”, then show them the empty spaces and the task they need to perform to fill those spaces.


  • Foursquare is a location-based social media site that allows people to “check in” at locations to unlock badges. Checking in at the same location on a frequent basis may be enough to make an individual the “mayor” of that place. Although it could be seen as a game, the compulsion to keep collecting badges and to remain as the mayor of a location definitely don’t harm sales at the retail locations, restaurants, and cafes that people check in to.
  • Online games such as World of Warcraft also encourage closure through leveling up and collection of in-game items.


This is an example of closure: people’s “Desire for a firm solution rather than enduring ambiguity.” The feeling of ambiguity or uncertainty puts people on edge. It is only when they have reached their goal or found a solution that people can feel comfortable setting the thing aside. The feeling of completeness that accompanies closure puts people at ease.

How to help people complete a set

  • Give people some achievements early in their interaction so that they get used to the concept.
  • Show them the empty slots that they need to fill with more achievements.
  • Provide levels of membership, with achievements to gain extra points, and potentially more benefits to reaching each level. Benefits may include the ability to do more of something that you want people to do anyway, such as moderate a forum.