respondents’ use of information in choice modelling surveys bill kaye-blake a, walt abell b, and...
TRANSCRIPT
Respondents’ use of information in choice modelling surveys
Bill Kaye-Blakea, Walt Abellb, and Eva Zellmana
aAgribusiness and Economics Research UnitbApplied Computing Group
Choice Modelling Workshop
Brisbane, 1-2 May 2008
Decision-making
• How people use information
• Theory – Simon, others
• Evidence
• Logit models derived from neoclassical paradigm
• Key question: does it make a difference?
Early attempt
• Paper survey with GM and non-GM alternatives
• Analysed choices– MNL, etc. (McFadden)
– Boundedly rational model (Simon)
• Results not brilliant
• Needed different data
Latest attempt
• Started from Hensher & Rose (debrief questions) and earlier BR work
• Teamed up with computer programmer and psychologist
• Computerised survey to capture information access
• Follow-up questions
Choice set display
Use of information
Unopened OpenedPercentage
unopened Group*
Texture 770 1840 29.5% a
Price 368 2242 14.1% b
Colour 815 1795 31.2% a
Production syst. 451 2159 17.3% c
Nutrition 434 2176 16.6% c
Country of origin 614 1996 23.5% d
* Similar within groups and statistically different between groups. Determined by chi-square tests, and are significant at the 0.01 level.
Figure 4. Respondent Behaviour During Survey
0
2
4
6
8
10
12
14
16
18
1 2 3 4 5 6 7 8 9 10
Question number
Tim
e (
se
co
nd
s)
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
Nu
mb
er
of
att
rib
ute
s
Seconds to respond Number of attributes ignored
Models
• Two models– Assumed full information– Only accessed information
• Mixed logit– Random parameters based on significance
• Panel models
• For unused information: coded in Limdep as -888
ML: Assumed full informationParameters Derived St dev
Value St. err. Value St. err.
Floury -0.348 0.144* 0.869 0.160**
Organic 0.349 0.178* 0.972 0.186**
GM -2.46 0.331** 2.14 0.339**
Omega-3 0.898 0.217** 1.23 0.220**
Low-GI 0.383 0.191* 0.814 0.228**
Australia -0.613 0.172** 0.670 0.253**
China -1.43 0.219** 1.16 0.255**
Price -1.37 0.144**
Pink -0.000 0.000
Yellow 0.245 0.126
Partworths: Full informationAttribute
Partworth(NZ$/kg)
Standard deviation
Floury -0.252 0.373
Organic 0.262 0.419
GM -1.84 0.923*
Omega-3 0.666 0.526
Low-GI 0.276 0.349
Australia -0.447 0.291
China -1.05 0.497*
Price -1.00 0.0873**
Pink -2.75E-05 9.98E-05
Yellow 0.179 0.0545**
ML: Accessed informationParameters Derived St dev
Value St. err. Value St. err.
Floury 2.52E-03 1.00E-03* 3.07E-03 1.37E-03*
Organic 0.677 0.0684** 9.06E-04 2.61E-03
GM -0.676 0.0684** 7.32E-04 3.21E-03
Omega-3 0.0918 0.0592 8.82E-04 1.51E-03
Low-GI -0.0886 0.0591 6.26E-04 1.64E-03
Australia 0.307 0.0770** 1.13E-05 1.61E-03
China -0.305 0.0770** 2.81E-05 1.61E-03
Price 2.38E-03 6.42E-04**
Pink -0.203 0.0573**
Yellow 0.206 0.0573**
Findings
• All available information not used
• Controlling for information use changes parameters– ‘Australia’: – +
– Price: – ~0
• Unexplained heterogeneity largely disappears