essay 1 airline search and purchase
TRANSCRIPT
Essay 1Modeling Online Browsing
and Purchase of Airline Tickets
Ciju Nair Washington University in St.
Louis
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Online Purchase Process
START BROWSE BUY
Prior experienc
e
3
Motivation
Extensive search and comparison before buying
No search or comparison, buy at first store
Online browsing
and purchase
Cont
inuu
m Feasible optionsOpportunity cost for time
Consideration set
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Motivation Consumers visit a limited set of websites
where they can buy airline tickets
Airline expenditure is a significant portion of overall online purchases
1832 households (Jul 02 - Dec 02) Mean Number of unique websites visited for a purchase 1.68 Expenditure in airline category in 6 months (US$) 570.09 Expenditure in all categories in 6 months (US$) 1018.22
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Choice Set
Expedia
Other travel portals (8 websites) All airline websites (20
websites) Normalized to “all airlines”
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Is there a benefit to modeling browsing and purchase jointly? What is the impact of first site visited and browsing duration?
Do websites differ in their attractiveness and conversion effectiveness?
What is the impact of browsing experience and prior purchase on current purchase and search?
What we don’t know
Yes. Improves in sample hit rate from 56% to 96% First site visited dynamically impacts browsing duration
and hence choice of purchase site
Airline websites are better than travel portals in attractiveness and conversion effectiveness
Experienced consumers first visit big brand travel portals There is an inverted U relationship between experience
and browsing duration
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Research Objective Investigate impact of early stages on later
stages
Understand factors that affect each stage
Investigate the dynamic impact of past purchase on current decisions
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Determinants of Browsing Limited information processing and
consideration set (Shocker et al. 1991, Roberts and Lattin 1997)
Prior Experience reduces search Prior product & category experience (Srinivasan
and Ratchford 1991, Brucks 1985) Inverted U relationship (Bettman and Park 1980,
Johnson and Russo 1984)
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Determinants of Browsing Cost and benefits of search
Perceived financial risk / benefit increases search (Punj and Staelin 1983)
Demographics Younger consumers search more in general
(Ward and Lee 2000) Broadband users search more (Yonish, Delhagen
& Gordon 2002)
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Determinants of Purchase First site visited and browsing duration
Primacy effect, consideration set and search costs (Anderson 1965)
Prior Experience Product experience (Bellinger et al. 1978, Janiszewski
1998, Roy 1994) Frequent visits (Moe and Fader 2004, Brynjolfsson and
Smith 2001) Category knowledge (Brucks 1985)
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Determinants of Purchase Prior Purchase
State dependence and inertia (Seetharaman, Ainslie and Chintaguta 1999 )
Expected Level of Expenditure Price and brand of online merchant are
important determinants of website choice (Brynjolfsson and Smith 2001)
Demographics Income dampens price sensitivities in online
markets (Degaratu, Rangaswamy and Wu 2000)
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Clickstream Prior Research
Browsing
Purchase
Browsing and Purchase on
multiple websites
Bucklin and Sismeiro 2003Park & Fader 2004Johnson et.al. 2004
Moe and Fader 2004aMontgomery et.al. 2006Brynjolfsson and Smith
2001Moe and Fader 2004b
Sismeiro and Bucklin 2004This paper
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Modeling Approach
STAGE 1 START
STAGE 2 BROWSE STAGE 3 BUY
Prior experienc
e
Jointly model the three stages of consumer decision process
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6 months of browsing & purchases: July 2002 to December 2002 100,000 households; 9183 surfed travel websites 3648 households made airline purchases
Selection criteria
1832 households satisfy selection criteria
Comscore Data
July December
OctoberEstimation
(last 3 months) Prior Experience(first 3 months)
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A Discrete–Continuous–Discrete Model
STAGE 1 START
Discrete
STAGE 2 BROWSE
Continuous
STAGE 3 BUY
Discrete
Prior experienc
e
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* *
*
1 if and only if , j
Travel portals j=1 to 4, Airlines is normalized to 0
ijt ijt ikt
f f f fj
f fijt it i ij i it ijt ijt
F F F k
F Z H S P I
Stage 1 : Discrete Choice of First Website
Categoryexperience
Latent Variabl
e
Expected levelof expenditure
DemographicsSite specificexperience
PriorPurchase
Randomshocks
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21 1 1 2
first website visited indicator
where is log(pages viewed) by individual i at time t for current purcha
'
seijt
d d d d d d dit it i it i i itp p
d
it
j ijt
F
D Z P I I H H
D
F
Stage 2 : Continuous Browsing Duration
DemographicsExpected level of expenditure
BrowsingDuration
Priorpurchase
Categoryexperience
Randomshocks
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* *
*
, j
first website visited indicatorbrowsin
1 if and only if U
g duration
p pj
ijt
it
ijt ijt ikt
pj
p p p pijtijt it ijtit
pit i ij i ijt
kU
F
U
D
F DU PZ H S I
Stage 3 : Discrete Choice of Purchase Website
Categoryexperience
Latent Variable Expected level of expenditure
DemographicsSite specificexperience
PriorPurchase
Randomshocks
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Correlation of with ( ) the endogenous decision variables in stage 2 & 3
Random effects model as opposed to IV approach as its not well behaved in a non-linear equation system
Dimensionality problem
Estimate nonlinear simultaneous 3 equation system with random effects
Large covariance matrix
Estimation Issues and d p
it ijt
( , , ; , , )f d p f d pi ij i ij i i i j
,it ijtD F
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Random Effects ; (stage1)
; (stage2) ; (stage3)
, , iid errors
, ,
f f f f fj ij ijt i
d d d d di it i
p p p p pj ij ijt i
f d pijt it ijt
f dij i ij
f fijt id dit ip pijt i
, , , individual specific and time invariant random effectp f d pi i i
The random effects are allowed to be correlated
( , , ; , , 1 to 4)f d p f d pi ij i ij ij i ij j
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Joint Estimation The likelihood function
As the likelihood is highly non-linear simulated maximum likelihood is used for estimation
i
stage (1)
i
stage (2)
i
stage (3)
Pr( 's history of first visits| )
Pr( 's history of browsing durations| )
Pr( 's history of purchases| )
i
i
L i
i
( ; )
: individual specific parameters
i
i
dF
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Model Estimation : Constrained Simulated Maximum Likelihood
Impose structure and exploit symmetry on to reduce dimensionality of parameters
Constrain to be positive definite during estimation
(15x15 matrix)
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Attractiveness Hotwire least likely to be visited first
Conversion Effectiveness As likely to buy from Hotwire as Orbitz
Stage 1 Stage 3 Parameters First site visited Purchase site Expedia -1.437 (0.020)* -3.806 (0.019)* Orbitz -1.624 (0.030)* -4.239 (0.167)* Hotwire -2.673 (0.021)* -4.168 (0.056)* Other travel portals -2.033 (0.006)* -4.283 (0.064)*
Results: Brand Strength
* indicates p < .001. Standard errors are in parentheses
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First visited site has a large impact on browsing duration and choice of the purchase site
Browsing duration increases purchase likelihood from portals
Joint model improves purchase hit rate from 56% to 96%
Stage 2 Stage 3 Parameters Browsing duration Purchase site
Expedia 0.686 (0.001)* Orbitz 0.577 (0.001)* Hotwire 0.771 (0.001)*
Stage 1 first visited site
Other travel portals 0.374 (0.001)* 5.223 (0.113)*
Expedia 0.281 (0.005)* Orbitz 0.444 (0.009)* Hotwire 0.293 (0.002)*
Stage 2 browsing duration Other travel portals
N/A 0.559 (0.007)*
* indicates p < .001. Standard errors are in parentheses
Results : Importance of First Site and Browsing Duration
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Change in choice probability Policy experiment
(effect of last purchase)
No prior purchase (choice
probability)
Last purchase
on Expedia
Last purchase on Orbitz
Last purchase
on Hotwire expedia.com 0.16 0.33 -0.05 -0.02 orbitz.com 0.13 -0.05 0.29 -0.02 hotwire.com 0.04 -0.02 -0.01 0.14
First site visited shares
All airlines 0.65 -0.26 -0.22 -0.09 expedia.com 0.15 0.36 -0.06 -0.03 orbitz.com 0.12 -0.06 0.34 -0.03 hotwire.com 0.04 -0.02 -0.02 0.18
Purchase shares
All airlines 0.67 -0.28 -0.25 -0.11
Prior purchase dramatically increases likelihood of first visiting as well as purchasing from a site for all brands
Simulation Experiment
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Prior category browsing experience increases likelihood of first visiting big brand travel portals
However it positively impacts purchase propensity only on Expedia and Hotwire
Results: Category Experience
Stage 1 Stage 3 Parameters First site visited Purchase site Expedia 0.008 (0.001)* 0.008 (0.001)* Orbitz 0.007 (0.001)* -0.001 (0.001)* Hotwire 0.007 (0.001)* 0.008 (0.001)* Other travel portals -0.072 (0.002)* -0.121 (0.002)*
* indicates p < .001. Standard errors are in parentheses
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Results: Browsing Experience and current Browsing Duration
Category experience effects on browsing duration is non-linear and has an inverted U shape
Stage 2 Parameters Browsing duration Category prior experience 0.426 (0.002)* Squared category prior experience -0.095 (0.001)*
* indicates p < .001. Standard errors are in parentheses
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Results: Prior Purchase and Browsing Duration
One prior purchase increases browsing duration compared to consumers who have no prior purchase
However it decreases browsing duration for heavy users
Both prior purchase and browsing experience increases likelihood of purchase on travel portal
Stage 2 Parameters Browsing duration Prior purchase (one) 0.017 (0.001)* Prior purchase (more than one) -0.244 (0.003)*
* indicates p < .001. Standard errors are in parentheses
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Results: Expected Level of Expenditure
Consumers with higher level of expenditure first visit travel portals and buy from them as opposed to airline websites
Stage 1 Stage 2 Stage 3 Parameters First site visited Browsing duration Purchase site Medium level 0.708 (0.014)* 0.465 (0.002)* 2.345 (0.043)* High level 0.689 (0.016)* 0.794 (0.001)* 0.457 (0.008)*
* indicates p < .001. Standard errors are in parentheses
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Results : w/ No-purchase option
Most results from no-purchase model are consistent with that of the conditional model
Inferences from significant interactions are consistent with our findings from the conditional model. However a lot more of the interactions are not significant in the no purchase model.
Higher site heterogeneity estimates also make us believe that we could be adding more noise to the data by incorporating data from no purchase transactions.
A more detailed comparison is included in the manuscript
Effect Inference Similar Dissimilar
First Site Visited and Browsing Duration X
Prior Browsing Experience X Prior Purchase X Consumer Demographics X Brand Strength X Interactions, Heterogeneitiesand Model Fit X
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Methodology Three stage model of browsing and purchase mapping
consumer decision processes
Findings Highlights impact of first site visited and search duration
on propensity to purchase Explores factors affecting consumer decisions in each
stage
Managerial implications Provides insight into consumer browsing and purchase
process Can be used as a benchmark model to investigate
effect of exogenous changes e.g. marketing mix or policy changes
effects of covariates (e.g. dynamic impact of last purchase) using simulation
Contribution
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START BROWSE BUY
Prior experienc
e START BROWSE BUY
Prior expeien
ce
Previous Cycle Next Purchase Cycle
Dynamic effect
BROWSE
BUY
START
Prior experienc
e
Virtual Cycle
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Next Steps and Future Research
Investigate basket or simultaneous purchases of airline, hotel and car rental products
Thank YouA recent version of this paper is available online at:http://students.olin.wustl.edu/~NAIRC/Online%20Search%20MS%20draft.zip