What I'm looking for is something practical and simple, but I would also like to hear about more complex approaches how to model something like this.
There are simple and complecated sAfter some sort of a discussion, here is my complete view of the things
I thinkThe problem
Aim: to understand how to price the field you are interestingcars in is related to conjoint analysis. a better way
SawtoothContext: in their decision process people solve several questions: do I need a car, if I do, what attributes I prefer most (including the price, because, being rational, I would like to my knowledgehave a car with best quality/price ratio), arecompare the leaders in this typenumber of analysis, though SPSSattributes between different cars and choosing valuing them Rjointly also provide the tools and libraries to perform the conjoint analysis.
This part of the applied statistics considerFrom the questions relatedseller position, I would like to how a particular group of costumers actually choose the product valuing different features ofset the latterprice as high as possible, but jointlyand sell the car as quickly as possible. The design of a questionnaire canSo if I set the price too high and am waiting for months it could be concentrated upon individual preferencesconsidered as not demanded on the market and marked with 0 comparing to very demanded attribute sets.
Observations: real deals that relates the attributes of a particular person, or you would probably likecar with the price set within the bargaining process (regarding the previous remark it is important to generalizeknow how long it take to set the preferences of a certain group of peopledeal).
To apply this analysis in practicePros: you have to know what cars, apartments, computers, cell phone plans wheredo observe the things that were actually bought or chosen, or at least the sample of respondents you study would buy or choose, if not facingon the budget constraint directly. Howevermarket, ifso you just collect the advertisements from newspapers or Internet the actual choices are hidden, because you do not observe them. To put it another way, you do not know in advance the qualitative answer to the questionguessing if there wasexist a person with high enough reservation price and/or money in the pocket to like this suggested set of attributes (notice that price is the attribute as well) at all. Knowing the latter, you could build some kind of multinomial logit model, where the price would be the impact variable.wants to buy a particular car
So to add more details, I think, we all need more details on:Cons:
- What doyour assumption is that market is efficient, meaning the prices you actually observe: are close to equilibrium
- you ignore the setvariants of car attributes only (price ISthat were not purchased or took too long to set the attributedeal, for examplemeaning your insights are biased, I would likeso you actually do work with latent variable models
- Observing the data for a long time you need to rentdeflate them, though the cheapestinclusion of the car withage partly compensates this.
Solution methods
The first one, as suggested by whuber, is the classical least squares regression model
Pros:
- indeed the best other attributes available, why not?) or some additional data not presented in your context partsimplest solution as it is the work-horse of econometrics
Cons:
- Whatignores that you believe could be your dependent variabledo observe the things incompletely (the probability of purchase to my mind is the most suitable herelatent variables)
- Do you needacts as the model for forecasting needs or just to understand what attributesregressors are independent one of the most influentialother, so the basic model ignores the fact that you may like blue Ford differently from blue Mercedes, but it is not the sum of marginal influence that comes from blue and Ford
And a bit more on the topic... In case of classical regression, since you are not limited in the degrees of freedom, to try also different interaction terms.
There areTherefore more complicated solution would be either tobit or Heckman model, you may want to my mind, several still open related questions:consult A.C. Cameron and P.K. Trivedi Microeconometrics: methods and applications for more details on core methods.
Pros:
- Decision making involves steps:you do I need a car, what features I value mostseparate the fact that people may not like some sets of attributes at all, how much I willingor some set of attributes has a small probability to pay forbe bought from the featuresactual price setting
- your results are not biased (answeringor at least less than in the last question you indeed perform something like simple regression modelfirst case)
- What prices doin case of Heckman you observe? Thoseseparate the reasons that are setmotivates to buy the particular car from the pricing decision of how much I would like to pay for this car: the first one is influenced by sellersindividual preferences, by buyers or the actual transactionsecond one by budget constraint
Cons:
- Both models are more data greedy, i. Without knowinge. we need to observe either the lattertime length between the ask and bid to equalize (if it is fairly short put 1, suppose youelse 0), or to observe 100 units of the sets that were ignored by the market
V6, red, automatic, 140hp, 2010, $300
And, finally, if you simply interested in how price influences the probability to be bought you may work with some kind of logit models.
We agreed, that whereconjoint analysis is not purchased and 1suitable here, because you do have different context and observations.
V6, blue, manual, 140hp, 2005, $100
that actually was? So what your conclusions based on regression analysis would be than?Good luck.