* Program \racd\racd6p2.do  August 1998
 
log using racd6p2.out, replace

* This STATA program reads in data and gives summary statistics and Poisson and
* negative binomial models for the recreational trips data studined in
* Chapter 6.4-6.5 and Chapter 12.6 of
*   A.C. Cameron and Pravin K. Trivedi (1998),
*   REGRESSION ANALYSIS OF COUNT DATA,
*   Econometric Society Monograph No.30, Cambridge University Press.
 
* The program does only a small part of the analysis in the book.

* To run you need file
*    racd6d2.asc
* in your directory

********** DATA DESCRIPTION
*
* A detailed discussion of the variables can be found in 
* C. Sellar, J.R. Stoll and J.P. Chavas (1985), 
* "Validation of Empirical Measures of Welfare Change: A Comparison of nonmarket 
* Techniques," Land Economics, 61, 156-175.  
* Data used with permission of Sellar et al. (1985)
* And also T. Ozuna and I. Gomaz (1995) 
* "Specification and Testing of Count Data Recreation Demand Functions," 
* Empirical Economics, 20, 543-550.

* The analysis of these data in the count data book is based on 
* S. Gurmu and P.K. Trivedi (1996)
* "Excess Zeros in Count Data Models for Recreational Trips"
* Journal of Business and Economics Statistics, 14, 469-477.
* "Multiple Bids as a Consequence of Target Management Resistance"

* 1:  Number of boating trips to Lake Somerville, East Texas, in 1980  (TRIPS or V3)
* 2:  Facility's subjective quality ranking  (SO)
* 3:  Respondent's taste for water-skiing  (SKI)
* 4:  Income - categorical variable  (I)
* 5:  Cost dummy variable; 1 if an annual user fee is paid at Lake somerville  (FC3) 
* 6:  Travel cost to Lake Conroe  (C1)
* 7:  Travel cost to Lake Somerville  (C3)
* 8:  Travel cost to Lake Houston  (C4)

********** CREATE OUTPUT FILE
*
di "racd6p2.do for Cameron and Trivedi RACD chapters 6.4-6.5 and 12.6"

********** READ DATA
*
* The Recreational trips data are in ascii file racd6d2.asc
* There are 659 observations on 8 variables with one lines per obs
* The data are fixed format with 
*   line 1  variables 1-8  5F7.0,3F11.0

infile TRIPS SO SKI I FC3 C1 C3 C4 using racd6d2.asc

********** DATA TRANSFORMATIONS
*

******** CHECK DATA: DESCRIPTIVE STATISTICS
*
describe
summarize

******** SAVE DATA AS STATA DATA SET
*
* save racd6d2, replace


********** POISSON REGRESSION 
*
poisson TRIPS SO SKI I FC3 C1 C3 C4 
nbreg TRIPS SO SKI I FC3 C1 C3 C4 

********** CLOSE OUTPUT
log close