What is estimation?
Estimation is basically approximation of time needed to complete an activity and activity can be anything. Activity may be driving from New Delhi to Mumbai or cooking food for 50 people or reading a 300 pages book.
Similarly estimation can be developing a data entry form or designing a search page for flight between cities.
Below are few important practices of agile estimation
- Estimates are shared and not done by individual
- Single estimate by whole team
- Top down estimate where team estimates requirement starting from Theme, epic then stories
- Ideal time is the time, which is spent only on project work without any interruptions.
- Elapsed time is the total time taken to finish the work.
It’s about relative terms
Agile estimate is relative terms and estimates has no direct link with man days or hours. Relative terms establishing a relation between multiple similar works then comparing which is big story, medium story or short story etc. Like designing a registration page can be a medium story but it may become big story if registration page required integration with CRM application.
Story Point Estimate
Story points are a unit of measure for expressing the overall size of a user story. We start with assigning a numeric estimate value to a user story. The raw value doesn't matter what matters is the relative values based on size (bigness and complexity). Team can use any unit to estimate like very big, big, medium, small, very small etc. Most appropriate is to use Fibonacci Series where story can be estimated like 1,2,3,5,8,13 points. Similarly Epic can be estimated like 20, 40, and 100.
Planning poker is a game that team play using deck of cards and every cards has number written on it. Every team member picks up a card against story and if all team member doesn't have same number then team discuss internally to understand each other logic about why someone estimated very high or very low. If story is not clear then team approach to product owner to get clarity about story. Team keeps playing this game till everyone agrees for approximately for same number.