Transcript Beyond Numbers

OXFORD SOFTWARE ENGINEERING
Software Engineering Services & Consultancy
Beyond Numbers
SPIN September 2002
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Slide 1.1
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Some views on measurement…
•
“What is not measurable, make measurable.”- Galileo
•
“When you can measure what you are speaking about and express it in numbers
you know something about it; but when you cannot measure it, when you cannot
express it in numbers your knowledge is of a meagre and unsatisfactory kind.” Lord Kelvin
•
“…This remark [above] has been quoted with an approval it does not altogether
deserve - it does not, for example, do justice to the work of Darwin or Pasteur, to
name only two of Kelvin’s contemporaries.” - G.U.Yule (statistician)
•
“You can’t control what you can’t measure.” - DeMarco
•
“Metrics is crap.” - Dijkstra
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Slide 1.4
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• Learning to Count
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• Learning to Count
– labelling
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• Learning to Count
– labelling
– ordering
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• Learning to Count
– labelling
– ordering
– differences
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• Learning to Count
– labelling
– ordering
– differences
– division
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• Learning to Count
– labelling
– ordering
– differences
– division
– sets
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Slide 1.10
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• Learning to Count
– labelling ( ~ nominal)
– ordering (ordinal)
– differences (interval)
– division ( ~ ratio)
– sets ( ~ absolute)
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• Learning to Count
– labelling ( ~ nominal)
– ordering (ordinal)
– differences (interval)
– division ( ~ ratio)
– sets ( ~ absolute)
• … a Measurement Maturity Model
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Slide 1.13
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Empirical
relational
system
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real world
mathematical world
Empirical
relational
system
Formal
relational
system
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measurement
Slide 1.15
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real world
mathematical world
Empirical
relational
system
Formal
relational
system
measurement
mathematics
and
statistics
Results
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Slide 1.16
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real world
mathematical world
Empirical
relational
system
Formal
relational
system
measurement
mathematics
and
statistics
Relevant
empirical
information
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interpretation
Results
Slide 1.17
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real world
mathematical world
Empirical
relational
system
Formal
relational
system
measurement
decisions
and
actions
Relevant
empirical
information
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mathematics
and
statistics
interpretation
Results
From Pfleeger 1998
Slide 1.18
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real world
mathematical world
Empirical
relational
system
Formal
relational
system
refined
measurement
better
decisions
and
actions
Relevant
empirical
information
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mathematics
and
statistics
improved
interpretation
Results
Slide 1.19
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Slide 1.20
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I
X
II
Y
X
III
Y
X
IV
Y
X
Y
10.00
8.04
10.00
9.14
10.00
7.46
8.00
6.58
8.00
6.95
8.00
8.14
8.00
6.77
8.00
5.76
13.00
7.58
13.00
8.74
13.00
12.74
8.00
7.71
9.00
8.81
9.00
8.77
9.00
7.11
8.00
8.84
11.00
8.33
11.00
9.26
11.00
7.81
8.00
8.47
14.00
9.96
14.00
8.10
14.00
8.84
8.00
7.04
6.00
7.24
6.00
6.13
6.00
6.08
8.00
5.25
4.00
4.26
4.00
3.10
4.00
5.39
19.00
12.50
12.00
10.84
12.00
9.13
12.00
8.15
8.00
5.56
7.00
4.82
7.00
7.26
7.00
6.42
8.00
7.91
5.00
5.68
5.00
4.74
5.00
5.73
8.00
6.89
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Slide 1.21
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I
II
12.00
10.00
10.00
8.00
8.00
6.00
6.00
4.00
4.00
2.00
2.00
0.00
0.00
2.00
4.00
6.00
8.00
10.00 12.00 14.00 16.00
0.00
0.00
2.00
4.00
III
14.00
12.00
12.00
10.00
10.00
8.00
8.00
6.00
6.00
4.00
4.00
2.00
2.00
2.00
4.00
6.00
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8.00
8.00
10.00 12.00 14.00 16.00
IV
14.00
0.00
0.00
6.00
10.00 12.00 14.00 16.00
0.00
0.00
5.00
10.00
15.00
20.00
Slide 1.22
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Slide 1.23
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validate
transaction
initialize
read
struct ure
set flag
re-estimat e
value
reallocate
import
history
convert
history
assign
owner
reformat
history
respond
check
user
align
with client
recalculate
struct ure
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clear
errors
validate
history
set
privilege
clear field
display
summary
flag
errors
Slide 1.24
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Val ida te
transa cti on
in itial ize
rea d stru ctu re
imp ort h istory
cle ar errors
resp ond
set fl ag
re-e sti mate valu e
i mpor t j a
va. uti l .*;
cl a
s s C lockT a
lk
che ck u ser
publ ic st ati c voi d mai n(St r ing[ ] ar gument s)
{
/ / get curr ent t im e and da
te
Cal endar now =C ale ndar .get Ins t ance() ;
i nt hour = now.get ( Cale ndar .H OU R_OF _DAY );
set privi leg e
i nt mi nute = now.get ( Cale ndar .M I NU TE) ;
i nt mont h= now. get( Cal endar. M ON TH) + 1;
con vert h istory
reforma t
i nt day= now. get( Cal endar. DA Y_OF_M O NTH );
i nt year =now .get (C ale ndar .Y EAR );
i mpor t j a
va. uti l .*;
/ /di s pla y gre et ing
cl a
s s C lockT a
lk
Sys te m .out . pri ntl n( " ) ;
f ( hour < 12)
publ ic st ati c voi d mai n(St r ing[ ] ar gument s)
{
/ / get curr ent t im e and da
te
al ign w ith
cle ar fi eld
Cal endar now =C ale ndar .get Ins t ance() ;
i nt hour = now.get ( Cale ndar .H OU R_OF _DAY );
i nt mi nute = now.get ( Cale ndar .M I NU TE) ;
di spla y su mmary
clie nt
i nt mont h= now. get( Cal endar. M ON TH) + 1;
i nt day= now. get( Cal endar. DA Y_OF_M O NTH );
i nt year =now .get (C ale ndar .Y EAR );
/ /di s pla y gre et ing
Sys te m .out . pri ntl n( " ) ;
rea llo cate
assi gn ow ner
f ( hour < 12)
Re calcu late
stru ctu re
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Val ida te
flag e rrors
history
Slide 1.25
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Slide 1.26
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• Validating Measurements
– do the data reveal the truth?
– is the representation accurate?
– are the data carefully documented?
– do the methods of display avoid spurious reading of the data?
– are appropriate contexts and comparisons shown?
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