Seb Rose engages in a Twitter discussion about estimating lengths. The canonical answer is that the length of a piece of string is twice the distance from the middle to the end. While relative estimation is advocated as an agile axiom, research does not necessarily prove people are better at relative than absolute estimation. Relative estimation still has value as a technique even if not proven superior in all cases. The discussion questions whether something appears small only because it is far away.

1. @sebrose
Seb Rose
How long is a
piece of string?

2. @sebrose
Canonical answer
Twice the distance from the middle to the end.
x 2

3. @sebrose
Agile axiom
Absolute estimation is hard

4. @sebrose http://cucumber.io

5. @sebrose

6. @sebrose
120 cm
40 cm60 cm
100 cm
70 cm

7. @sebrose
... these studies which have for a few years now
given rise to the claim that "research shows that
people are better at relative than absolute
estimation" do not in fact seem to square with
that claim.
This doesn't entail that relative estimation doesn't
work - only that it is not proven.
http://guide.agilealliance.org/guide/relative.html

8. @sebrose
12 cm
4 cm
6 cm
10 cm
7 cm

9. @sebrose
Is it small,
or just far away?

10. @sebrose

11. @sebrose