The cards are numbered as they are to account for the fact that the longer an estimate is, the more uncertainty it contains. Thus, if a developer wants to play a 6 he is forced to reconsider and either work through that some of the perceived uncertainty does not exist and play a 5, or accept a conservative estimate accounting for the uncertainty and play an 8.
Monday, August 31, 2009
Planning Poker: one card only!
On Tuesday night, during a marketing event, I had a short discussion with someone from Cyrus Innovation about planning poker. I had a specific question: "should we use multiple cards when making our estimate?" The idea behind using multiple cards is to form numbers that are not available in the list, for example, use 1 and 3 to play a 4. His opinion was that no, we should not do this. The cards have those values (0, ½, 1, 2, 3, 5, 8, 13, 20, 40, 100) for a reason. According to Wikipedia: