Peter Lenk

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In a discrete choice situation, information about the tastes of each sampled customer is inferred from estimates of the distribution of tastes in the population. First, maximum likelihood procedures are used to estimate the distribution of tastes in the population using the pooled data for all sampled customers. Then, the distribution of tastes of each(More)
Multivariate economic and business data frequently suffer from a missing data phenomenon that has not been sufficiently explored in the literature: both the independent and dependent variables for one or more dimensions are absent for some of the observational units. For example, in choice based conjoint studies, not all brands are available for(More)
for specific helpful comments. Excellent research assistance was provided by Helder Palaro. We are grateful to two anonymous referees for their valuable suggestions on improving the paper. We accept responsibility for all remaining errors. Abstract Rating transition matrices for corporate bond issuers are often based on fitting a discrete time Markov chain(More)
We investigate the causal effect of position in search engine advertising listings on outcomes such as click-through rates and sales orders. Since positions are determined through an auction, there are significant selection issues in measuring position effects. A simple mean comparison of outcomes at two positions is likely to be biased due to these(More)
We investigate the causal effect of position in search engine advertising listings on outcomes such as click-through rates and sales orders. Since positions are determined through an auction, there are significant selection issues in measuring position effects. Correlational results are likely to be biased due to the selection in position induced by(More)