Scrum Masters insist on having the whole teams at plannings and other Scrum events. When team asks "why?" first answer is that The Scrum Guide says so. But why? Well..cause it's reasonable? In 2014 and 15 I made a series of experiments about the wisdom of the crowds in different groups (more than 100 people all together) trying to verify the F. Galton's discovery from the beginning of XX century (the crowd at a county fair accurately guessed the weight of an ox when their individual guesses were averaged). I added an aspect of diversity in possibilities of comparison during estimation to conclude for the Scrum teams about refinement process, plannings and daily meetings. We conducted the experiment during the meeting too (results on the last slides).

1. Wisdom of the
crowds
@RadekLont
#abe16

2. (1)
(2)
(3)

6. DIVERSE GROUP
ClibPDF - www.fastio.com
Francis Galton
(1907)
INDEPENDENT DECISION
(2004)
(2004)
(2011)

7. DIVERSE GROUP
INDEPENDENT DECISION
WHAT IF…

9. REAL: 112
MEAN: 116
MEDIAN: 115
120 votes
3,5%
90
107,5
125
142,5
160
guesses mean value real value

10. REAL: 112
MEAN: 111,2
MEDIAN: 112
15 students
REAL: 112
MEAN: 112,8
MEDIAN: 111
6 agilers

11. REAL: 72
MEAN: 69,5
MEDIAN: 70
100 votes
2,7%
40
52,5
65
77,5
90
guesses mean value real value

12. MEAN: 74
MEDIAN: 72
26 mix
MEAN: 69
MEDIAN: 71
8 Dev Team
REAL: 72

13. 120 votes
REAL: 828
MEAN: 903
MEDIAN: 760
9%
8%
0
500
1000
1500
2000
2500
3000
guesses mean value real value

14. REAL: 828
MEAN: 519
MEDIAN: 417
6 agilers

15. DIVERSE GROUP
INDEPENDENT DECISION
PROBE over DATA

16. BACKLOG REFINEMENT
is a PROCESS
DEVOPS way is to
EXPERIMENT
Assure QUALITY
at the source

17. @RadekLont
#abe16
Wisdom of AbE crowd?

18. REAL: 112y 828m 75kg
MEAN: 115 700 78
MEDIAN: 115 765 77
139 votes
#AbE16
2,5% 15%
7,5%
4%
2,5%