What Story Points are?
written by gunther gerlach-2009
Story points are used to measure the effort required to implement a story and is measure based on Size, Factorial, Squares or Fibonacci techniques. This is a random measure used by Scrum teams.
This is mainly done as we as humans and as managers are better at abstract terms. If we use hours as a way to size stories, then the managers in the room have questions, teams don’t immediately feel comfortable with hours…
|
Duration |
Size |
Factorial |
Squares |
Fibonacci |
|
1 – 3 day |
X Small |
1 (1!) |
1 – 12 |
1 |
|
3 – 5 days |
Small |
2 (2!) |
4 – 22 |
2 |
|
5 – 7 days |
Medium |
6 (3!) |
9 – 32 |
3 |
|
7 – 10 days |
Large |
24 (4!) |
16 – 42 |
4 |
|
> 10 days |
X Large |
120 (5!) |
25 – 52 |
5 |
In simple terms its a number that tells the team how hard the story is. In a sprint your team does two small stories and two medium then your velocity is 9 * 2 + 4 * 2 = 26 ( if you are following the squares technique). Square is simple and works quite well.
In most cases a story point range is 1, 2, 4, 8, 16 or X Small, Small, Medium, Large, Extra Large
It is a relative term and does not directly co relate to actual hours. Since story points have no relevance to actual hours, it makes it easy for scrum teams to think abstract about the effort required to complete a story.
Story points do give some indication of how much time was spent in a sprint.
Example let’s say at the end of a 10 day sprint a team of 4 covers 40 story points.
10 days = 10 * 8 working hours = 80 hours. = 320 total hours as there are 4 developers.
That equated to 160 pairing hours. 160 divided by 40 = 4 hours pair hours per story point.
