Seung-Hyun Hong, "Measuring the Effect of Napster on Recorded Music Sales: Difference-in-differences Estimates under Compositional Changes", Journal of Applied Econometrics, Vol. 28. No. 2, 2013, pp. 297-324. The file named "cex_basefile97_02.csv" contains the data. It is zipped in the file shh-data.zip. The data are extracted from the Consumer Expenditure Survey, and are saved in an ASCII file in a comma-separated format. See below for more information. Several code files are zipped in the file "shh-codes.zip". This file includes the following files: ddm_boostrap.pl Runs all the codes below to implement the DDM estimation as well as the bootstrap estimation. Running this code will implement all the codes below sequentially. propensity_score.sas Loads "cex_basefile97_02.csv" and estimates the propensity scores and outputs files to be used by "llm.f90". llm.f90 Computes the DDM estimates. bootstrap_ddm.sas Creates bootstrap samples, estimates the propensity scores, and outputs files to be used by "bootstrap_llm.f90". bootstrap_llm.f90 Computes the DDM estimates using bootstrapped samples. bootstrap_se.sas Computes the standard errors. The data in cex_basefile97_02.csv are extracted from the Consumer Expenditure Survey. The file is an ASCII file in a comma separated format. The number of observations is 107,650. The file includes 53 variables in the following order. newid household identification number intno interview number year year firmth first month of the interview nint 1 if household does not have the Internet cdall expenditure on recorded music age age of reference person in the household white 1 if the reference person is white black 1 if black male 1 if male hsgrad 1 if highest education is high school graduate lesscol 1 if some college, less than college colgrad 1 if college graduate fam_size family size of the household nchle11 the number of children younger than 11 nch1217 the number of children ages between 12 and 17 persot64 the number of persons older than 64 hw 1 if the household is family with husband and wife only single 1 if single hwyng 1 if family only with husband and wife, and age under 40 hwchbs 1 if husband and wife with children before school hwchis 1 if husband and wife with children in school hwchas 1 if husband and wife with children after school spchbs 1 if single parent with children before school spchis 1 if single parent with children in school hwold 1 if family only with husband and wife, and age over 45 retired 1 if retired headwrk 1 if the head of the household is working spouwrk 1 if the spouse of the household is working incweek1 the number of weeks in a year that head worked inc_hrs1 the number of hours in a week that head worked incweek2 the number of weeks in a year that spouse worked inc_hrs2 the number of hours in a week that spouse worked fincreal real final income before tax (in $10,000) owner 1 if the household owns house renter 1 if rents house ne 1 if resides in northwest census region mw 1 if resides in midwest census region west 1 if resides in west census region urban 1 if resides in urban area msa 1 if resides in metropolitan statistical area ps4mil 1 if resides in area with population size over 4 million ps1mil 1 if population size between 1.2 million and 4 million ps330k 1 if population size between 330 thousand and 1.2 million ps125k 1 if population size between 125 thousand and 330 thousand tv the number of televions in the hosuehold comp the number of computers sound the number of sound components vcr the number of VCRs vehq the number of vehicles coldormi 1 if the household is living in college dormitory occucod1 occupation codes weight CEX weight All the ASCII files are in DOS format. Unix/Linux users should use "unzip -a".