2. ::
Which candidate will you ‘buy’?
Conjoint Analysis, from marketing studies to electoral research
Janko Hočevar & Toni Gril
Summer School in Methods and Techniques 2009
3. :: Agenda
Part I.
• Intro to Conjoint Analysis
- Idea
- History
- Flavors
Part II.
• Conjoint Analysis in the context of political research
• Case studies:
- Slovenian parliamentary elections 2000
- Slovenian presidential elections 2002
• Q&A
3
4. ::
Part I.
Intro to Conjoint Analysis
Ask people what they want, and they say, “the best of everything”.
Ask them what they would like to spend, and they say, “a little as possible”.
– Bryan K. Orme
5. ::
Slide borrowed from: Batsell R., Chrzan K., Baggett S., SawtoothSoftware Conference, Barcelona 2008.
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6. ::
Slide borrowed from: Batsell R., Chrzan K., Baggett S., SawtoothSoftware Conference, Barcelona 2008.
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7. ::
Slide borrowed from: Batsell R., Chrzan K., Baggett S., SawtoothSoftware Conference, Barcelona 2008.
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8. ::
John
Slide borrowed from: Batsell R., Chrzan K., Baggett S., SawtoothSoftware Conference, Barcelona 2008.
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9. ::
Mary
Slide borrowed from: Batsell R., Chrzan K., Baggett S., SawtoothSoftware Conference, Barcelona 2008.
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10. ::
Bubba
Slide borrowed from: Batsell R., Chrzan K., Baggett S., SawtoothSoftware Conference, Barcelona 2008.
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11. ::
Romantic 3,9
Sexy 3,8
Entertaining 4,4
Exciting 4,2
Calm 4,6
Laid back 4,2
Outdoorsy 4,2
Family-Oriented 4,5
Fancy 4,0
1 2 3 4 5
• Bias toward high importance in ratings
• Lack of discrimination
• Different respondents use the scale differently
11
12. ::
• Ask Direct Questions about preference:
- What brand do you prefer?
- What Interest Rate would you like?
- What Annual Fee would you like?
- What Credit Limit would you like?
• Answers often trivial and unenlightening (e.g. respondents prefer low fees to
high fees, higher credit limits to low credit limits)
12
13. :: CA Idea
• People cannot reliably express how they weight separate features of the
product/service
• But can evaluate the overall desirability of a complex product/service profile – a
more realistic approach
- Based on a function of the value of its separate (yet conjoined) parts
• We can break product/services into features (attributes & their levels)
• Based on how people evaluate the combined features (profiles) we can deduce
the preference scores people might have assigned to individual features of the
product/service
- That are the result of those overall evaluations
• A back-door, decompositional approach for estimating people‟s preferences,
rather than an explicit approach of simply asking people to rate, rank, .. separate
features
13
14. :: CA Short History
• Based on the work by:
- Luce & Tukey in 60‟s
Luce, D. & J. Tukey ,1964. Simultaneous conjoint measurement: A new type of fundamental measurement. Journal of
Mathematical Psycchology
- McFadden in 70‟s - Discrete choice methods
McFadden, D. 1974. Conditional logit analysis of qualitative choice behavior. In P. Zarembka (ed.), Frontiers in
Econometrics, pp. 105-142. New York: Academic Press.
• Early 70s
- work of P. Green:
Green, P. & V. Rao 1971, August. Conjoint measurement for quantifying judgemental data. Journal of Marketing
Research
- work of R. Johnson:
• Johnson, R. 1974, May. Trade-off analysis of consumer values. Journal of Marketing Research
• 80‟s
- Green & Wind: application of conjoint analysis to help Marriott design its new Couryard Hotel
• S. Herman & Bretton-Clark software released software system
- R. Johnson (at Sawtooth Software) released a software system Adaptive Conjoint Analysis (ACA)
• 90‟s
- Discrete Choice overtakes Traditional Conjoint methods
• Commercial software released (SawtoothSoftware CBC)
• Application of of hierarchical Bayes (HB) methods to estimate individual-level models from discrete choice data (led
by G. Allenby of the Ohio State University)
• 00‟s and beyond
- Maximum-Difference Scaling
- Adaptive Choice Based Conjoint (ACBC) software released by SawtoothSoftware in 2009
14
15. :: Two broad types of CA
• “Traditional” CA
- uses data collected from sequential ratings, rankings or graded (rated) paired
comparisons followed by an analysis using simple linear models
- Use of “choice simulators” to predict individuals‟ preferences and choices
• No Choices are observed
• Choice-based Conjoint Analysis (CBC).
- uses data collected from a series of choices (from “choice sets”), followed by an
analysis using probabilistic choice models.
- Use of choice simulators to predict individuals‟ preferences and choices
• Choices are observed
15
16. :: CA Terminology
• Attribute
- A feature of product/service: Brand, Price, Pack type,...
• Attribute Level
- A value or range of variation for an attribute:
• Coca Cola, Pepsi,..., 0.5€, 0.6€,..., 0,33 l Can, 0,5 l Plastic Bottle
• Profile / Concept
- A combination of attribute levels: Coca-Cola at 0.5€ in a 0,33 l Can
• Design
- the attribute combinations that make up product/service profiles/concepts and how
those profiles/concepts are combined within tasks.
16
17. :: Design
• Orthogonality:
- each level appears an equal number of times with every other level of different
attributes. (zero correlation between pairs of attributes)
• Level Balance:
- within each attribute, each level appears an equal number of times.
• Minimal Overlap:
- achieve maximum variation across levels of an attribute within a (choice) task
(try not to repeat a level).
• Designs which are orthogonal and balanced are optimally efficient.
• In the real world: well-balanced, "nearly orthogonal“ designs
17
18. :: CA Research Process
• Identify attributes that underlie consumer preferences for products/services.
• Select levels or values of each attribute to represent ranges of variation in real
markets
• Create product or service profiles generated from some type of experimental
design
• Administer to a sample of respondents
• Analyze the data
- Relative importance
- Utilities or Part-Worth's
- Simulations
- Optimizations
18
19. :: CA Data Analysis
• Parameter estimates
- OLS
- MNL (HB)
• Simulations
- First choice rule
- Purchase Likelihood
- Share of Preference
- Randomized First Choice
19
20. :: Basic Flavors
• CVA – Conjoint Value Analysis (traditional)
- One or two full profile concepts
- One design / experiment
- Rating
- OLS
- Individual parameter estimation
20
26. ::
• CBC – Choice Based Conjoint
- Two or more concepts
- Full or partial profile
- Multiple designs / experiments
- Alternative specific designs
- Fixed / Constant alternatives
• (e.i. I wouldn‟t buy anything; I‟d stay with my current service; NONE)
- Choices, allocations (Constant Sum allocation)
- Group / Semi-individual parameter estimation (MNL HB)
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30. :: What can we do with Conjoint data?
• Base case predictions linked with descriptive data
- who chooses what?
• Great input for segmentation (cluster analysis, latent class,...)
• Simulations (what if?)
- Sensitivity analysis (what if? systematically)
• Optimizations (best configurations)
• A simulator mimics a certain situation, that may or may not happen in reality (like
a flight simulator).
• The purpose is to estimate the probable effects of products/services.
• For this, the simulator needs input
- Data to describe the situation (scenario definition)
- Data on how consumers react (utilities from conjoint)
- Definition of the calculation
• Changing (part of) this data will result in new scenarios and new output
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31. ::
Part II.
Conjoint Analysis in the context of political research
Case studies:
Slovenian parliamentary elections 2000
Slovenian presidential elections 2002
32. :: The premise
• The outcome of presidential or party contest is influenced by many factors
- party identification, candidate personality, campaign strategy and tactics, financing,
etc.
• In a real „purchase situation‟, „consumers‟ do not make choices based on a
single attribute. Consumers examine a range of features or attributes and then
make judgments or trade-offs to determine their final purchase choice.
• This is just as true for the „choice‟ made in political situations, such as assessing
the viability of a candidate, determining the support of various political,
economic, social issues.
Product:
• Candidate (not „branded‟) / Political Party (not „branded‟ but with issues
positions)
• Political Parties / Candidates are:
- Managed as Products/Services
- Advertised as Poroduct/Services
- Communicated as Products/Services
32
33. ::
Slovenian parliamentary elections 2000
Client: The Mladina Magazine
34. :: Slovenian parliamentary elections 2000
• Determine issues relative importance to voters, the most and least popular
position on each issue, the impact of a given position on voting behavior, and
the relative strength of different candidate profiles.
• To do that, we asked each respondent to rate a series of hypothetical pair of
candidates who have either a „liberal‟, „centrist‟, or „conservative‟ position on
each of 5 issue categories.
• Issues were the subject of debate in the campaign, and the position descriptions
were determined from positions that the candidates have actually taken and
were exposed in the media.
• C.A.T.I., n = 601
• ACA
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35. :: Slovenian parliamentary elections 2000
5 attributes & a total of 14 levels:
• History: • Welfare
- Past injustices are settled, what is important - Every single individual should take care of
is the future his/hers social welfare (health care, pension
- There is no future unless we settle past welfare,...)
injustices - The state and every single individual should
- The future must be a priority, but we must take care of social welfare
never forget the past injustices - The state should take care of the whole
social welfare of its citizens
• Roman-Catholic church • Lustration
- RCC should be included in the political - Those who were appointed to management
decision making positions by the former political system,
- RCC should be consulted only with the should stay there if they are capable and
essential political issues qualified
- RCC must be excluded from political sphere - We should remove all those who were
appointed to management positions by the
• Equalitarianism former political system
- The state should determine maximum wage
of all managers in all companies
- The state should determine maximum wage
only of managers in state owned companies
• 10 pair
- The state should not interfere with managers • 2 attributes in pair
wages
35
36. :: Slovenian parliamentary elections 2000
Relative importance of issues
Lustration
15,5% Welfare
22,9%
Equalitarianism
19,7%
Roman-Catholic
church
21,6%
History
20,3%
36
37. -50,0
-40,0
-30,0
-20,0
-10,0
0,0
10,0
20,0
30,0
Past injustices are settled, future is
important
2,6
There is no future
-20,4
History
The future must be a priority 17,8
Utilities / Part Worth's
RCC should be included
-22,7
RCC should be consulted
8,3
RCC must be excluded
14,4
Roman-Catholic church
The state should determine
maximum wage
-0,3
:: Slovenian parliamentary elections 2000
The state should determine
maximum wage only state owned
companies
9,5
Equalitarianism The state should not interfere
-9,2
Every single individual should take
care
-39,9
The state and every single individual
should take care
19,7
The state should take care of the
Welfare
whole social welfare
20,1
Stay if they are capable and qualified
20,9
Lustration
We should remove all
37
-20,9
38. :: Slovenian parliamentary elections 2000
• Max – Min horse race
- Max purchase likelihood = 62,43%
- Min purchase likelihood = 20,47%
- Max : Min | 80,6% : 19,4%
38
39. 10
12
0
2
4
6
8
-16
-14
-12
-10
-8
-6
-4
-2
0
Past Past
injustices injustices
are settled, are settled,
2,58
-3,63
There is no There is no
future
0
future
The future
-8,62
The future
History
History
must be a must be a
0
priority
5,4
priority
RCC RCC
should be should be
0
included included
-8,44
RCC RCC
should be should be
Min = 20,47%, ABS % gain / loss
Max = 62,43%, ABS % gain / loss
consulted consulted
4,55
-1,87
RCC must RCC must
be be
0
excluded excluded
5,36
Roman-Catholic church
Roman-Catholic church
The state The state
should should
determine determine
1,95
-1,82
The state The state
:: Slovenian parliamentary elections 2000
should should
0
determine determine
2,66
The state The state
should not should not
0
Equalitarianism
Equalitarianism
interfere interfere
-4,15
Every Every
single single
0
individual individual
-13,5
The state The state
and every and every
single single
9,89
-0,11
The state The state
Welfare
Welfare
should take should take
0
care of the care of the
10,31
Stay if they Stay if they
are capable are
0
and capable
6,8
We should We should
Lustration
Lustration
remove all
0
remove all
39
-10,16
40. :: Slovenian parliamentary elections 2000
• Issues positions to avoid / to put out
- Where? (geography, not really applicable in Slovenia), to whom? (gender, age,...) ...
• Voter‟s profile
• (Respondent) Party identification profile
• Handling “don‟t knows” or “refused to answer” modalities
40
41. ::
Slovenian presidential elections 2002
Client: FDV
42. :: Slovenian presidential elections 2002
• Determine issues relative importance to voters, the most and least popular
position on each issue, the impact of a given position on voting behavior, and
the relative strength of different candidate profiles.
- To do that, we asked each respondent to rate a series of hypothetical pair of
candidates who have either a „liberal‟, „centrist‟, or „conservative‟ position on each of
four issue categories.
- Issues were the subject of debate in the campaign, and the position descriptions
were determined from positions that the candidates have actually taken and were
exposed in the media.
• Determine relative importance of demographic characteristics of a presidential
candidate and the impact on voting behavior.
- To do that, we asked each respondent to rate a series of hypothetical pair of
candidates described with demographic characteristics.
• C.A.T.I., issues n = 750, demo n = 786
• ACA
42
43. :: Slovenian presidential elections 2002
Political issues: Demographic profile:
3 attributes & a total of 7 levels: 3 attributes & a total of 8 levels
• History: • Gender
- Past injustices are settled, what is important - Male
is the future - Female
- There is no future unless we settle past • Age
injustices
- 40 yrs or younger
• Roman-Catholic church - Between 40 and 60 yrs old
- RCC should take active part in the political - Older than 60 yrs
decision making • Background
- RCC should be consulted only with the - In Politics
essential political issues - In Economy
- RCC must be excluded from political sphere - In other profession (health, science, culture,
• Foreign policy education, sport,...)
- Joining NATO, EU and to open way for
foreign investments takes careful • 12 pair
consideration of every step we make • 2 / 3 attributes in pair
- There should be no hesitation with joining
NATO, EU and to open way for foreign
investments
• 10 pair
• 2 / 3 attributes in pair
43
44. :: Slovenian presidential elections 2002
Relative importance of issues Relative importance of demo
Gender
Background
17,1%
Roman-Catholic 37,7%
church History
46,0% 29,5%
Foreign policy Age
24,5% 45,2%
44
45. -40,0
-20,0
0,0
20,0
40,0
60,0
80,0
Past injustices are settled, future is
important
26,1
There is no future
History
-26,1
RCC should take active part
-33,3
RCC should be consulted
Issue Utilities / Part Worth's
-24,8
RCC must be excluded
58,2
Roman-Catholic church
NATO, EU, ... Careful consideration of
every step
25,9
NATO, EU,... No hesitation
Foreign policy
:: Slovenian presidential elections 2002
-25,9
-60,0
-40,0
-20,0
0,0
20,0
40,0
60,0
Male
7,1
Female
Gender
-7,1
40 yrs or younger
-10,2
Between 40 and 60 yrs old
51,5
Age
Older than 60 yrs
-41,3
In Politics
-0,3
In Economy
19,7
45
Background
Demo Utilities / Part Worth's
In other profession
-19,4
46. :: Slovenian presidential elections 2002
Winner Max purchase likelihood = 62,67%, ABS % gain / loss
0,0
0,0 0,0 0,0
-2,0
-3,0
-4,0
-4,1
-6,0
-8,0
-7,1
-10,0
-12,0
-11,2
-14,0
-16,0
-16,5
-18,0
Male Female 40 yrs or Between 40 Older than In Politics In Economy In other
younger and 60 yrs 60 yrs profession
old
Gender Age Background
Male – Female horse race (same profile; 40-60 yrs old, background in economy)
- Randomized First Choice rule:
• Male : Female | 52,9% : 47,1%
46
47. :: Slovenian presidential elections 2002
Official result (2nd round)
• J. Drnovšek = 56,54 %
• B. Brezigar = 43,46 %
Simulation:
• J. Drnovšek
(Male, 40-60 yrs old, background in politics):
56,20%
• B. Brezigar
(Female, 40-60 yrs old, background in other profession /public prosecutor/):
43,80%
47
48. ::
“Life is one big conjoint analysis . . . one tradeoff
after another.”
– Paul E. Green
48