About the first wave of the survey(KHPS2004)

The first wave of the survey was implemented in the following manner

- Coverage of the Survey
  Males and females aged between 20 and 69 years as of 31 January 2004.
  (Males and females born between February 1934 and January 1984).
  According to the population estimates for February 2004, this population was about 85.75 million or 67.2% of the total population.

- Day for the Survey
  The survey was implemented on 31 January 2004.

- Choice of the Survey Subjects
(1)Sample Size
   4,000 People (However, the files contained in the CD-ROM contain data on 4,005 individuals of whom 5 individuals were backups)

(2)Method for Obtaining Sample
   Two stage stratified sampling (first stage was the survey area, and the second stage was the individual)

(3)Choice of Survey areas.
   Census enumeration districts for the 2000 National Census were used as the survey areas.
   First, the nation as a whole was stratified into 24 strata according to region and city size,
   for each stratum the sample size was determined by the stratum’s population share of National Residents
   Register’s population as of 31 March 2003. Next, based on a sample of about 10 for each sampling area,
   the number of sampling areas in each stratum was determined, and the required number of survey
   areas were chosen at random for each stratum.

          Details of the allocation of the sample across regions and city size are as follows

   14 Large Cities Other Cities Towns and Villages Total
Hokkaido 61 80 38 179
Tohoku 32 162 101 295
Kanto 498 693 146 1,337
Chubu 69 476 181 726
Kinki 174 404 81 659
Chugoku 36 142 55 233
Shikoku  -  83 42 125
Kyushu 75 235 136 446
Total 945 2,275 780 4,000

(4)Choice of Survey Respondents
Survey respondents The National Residents Register or the Electoral Roll for the chosen survey area
was used as the sampling register, Limiting the sample to eligible individuals, and based on designated
numbers and sampling interval for the survey area about 10 individuals were sampled.
However, when the sequencing of the sampling register did not follow the area sequencing or was not ordered
according to the Japanese alphabet within an area, using a map for residences every third residence was sampled
within the required area.

 (5)Choice of the back-up Sample
For this sample, in order to obtain a sample of 4,000 individuals, when an individual originally chosen
for survey did not take part in the survey, he or she was replaced by a person from the back up sample
that had been previously determined.
The back up sample was chosen to have the same sex (male or female), the same age grouping
(in their 20s, in their 30s, in their 40s, in their 50s, in their 60s) as the original individual.

- Survey Method
The survey was implemented by the drop-off pick-up (DOPU) method whereby the by the surveyor distributes
the questionnaire to the survey respondent, and then the surveyor visiting the respondent again to collect
the questionnaire that had been completed by the respondent.

- Types of Questionnaires
 Two types of questionnaires that differed according to whether there was a spouse or not were used.


1st wave(KHPS2004) questionnaire PDF