DOI: 10.3886/icpsr30822.v2
title: Survey of Midlife in Japan (MIDJA), April-September 2008
title: Version 2

description: The MIDJA study is a probability sample of Japanese adults (N = 1,027) aged 30 to 79 from the Tokyo metropolitan area. Survey data were collected on sociodemographic characteristics (age, gender, marital status, educational status), psychosocial characteristics (e.g., independence/interdependence, personality traits, sense of control, goal orientations, social support, family obligation, social responsibility), mental health (depression, anxiety, well-being, life satisfaction), and physical health (chronic conditions, health symptoms, functional limitations, health behaviors). These measures parallel those in a national longitudinal sample of midlife Americans known as MIDUS (ICPSR 4652: MIDUS II and ICPSR 2760: MIDUS I). The central objective is to compare the Japanese sample (MIDJA) with the United States sample (MIDUS) to test the hypothesis that the construct of interdependence predicts well-being and health in Japan, whereas the construct of independence predicts well-being and health in the United States. Cultural influences on age differences in health and well-being are also of interest.
description: The overarching goal of the MIDJA (Midlife in Japan) study was to conduct a multidisciplinary study of health and well-being in a sample of middle- and older-aged Japanese adults. A first primary aim was to collect survey data on a probability sample of adults from the city of Tokyo, Japan. A second aim was to recruit a subsample of respondents from the above survey to participate in a related biomarker study (to be released for public use at a later date).
description: Central Research Services (CRS) based in Tokyo, Japan, conducted the MIDJA Survey from April 2008-September 2008. All respondents were sent an advance letter that included an explanation of the research and an invitation to complete a self-administered questionnaire (SAQ) approximately 46 pages in length. Monetary incentives were used to maximize participation; individuals completing the survey received 3,000 yen (~$28-30). Japanese survey research relies on a "deliver and pick-up" method of questionnaire administration, thus written consent was obtained when the SAQ was delivered to the participant's home.
description: ICPSR data undergo a confidentiality review and are altered when necessary to limit the risk of 
				disclosure. ICPSR also routinely creates ready-to-go data files along with setups in the major 
				statistical software formats as well as standard codebooks to accompany the data. In addition to 
				these procedures, ICPSR performed the following processing steps for this data collection:
			   		Standardized missing values.; Created online analysis version with question text.; Checked for undocumented or out-of-range codes..
description: Presence of Common Scales: 
					See the "Documentation of Scales and Constructed Variables in MIDJA" available through the ICPSR and NACDA Web sites for complete information regarding the scales for the MIDJA data collection.
description: Response Rates: 
					The overall response rate was 56.2 percent. Reasons for nonresponse included: moved, address unknown, absent during time of survey, illness/injury, hospitalized, deceased. Detailed information regarding the response rates for various aspects of the MIDJA data collection is located in the following document: "Description of the MIDJA Study." This document is available for download through the ICPSR and NACDA Web sites.
description: Datasets: 
					
						DS1: Survey of Midlife Development in Japan (MIDJA), April - September 2008
description: Midlife in the United States (MIDUS) Series
description: mail questionnaire
description: self-enumerated questionnaire
description: Noninstitutionalized, Japanese-speaking adults, aged 30-79 and living in one of the 23 wards of Tokyo from April 2008-September 2008.
description: The MIDJA survey data were collected from a total of 1,027 participants. Central Research Services (CRS) based in Tokyo, Japan, conducted the MIDJA Survey from April 2008-September 2008. The sample was selected from the Basic Resident Register Book for the 23 wards in Tokyo, Japan, via two-stage stratified random sampling. Within each ward 5 groups were created based on age (30-39, 40-49, 50-59, 60-69, 70-79) and stratified by gender. Thus, ten strata, based on gender and age were created. For each strata a total of 100 samples are allotted and proportionally distributed among each ward based on the number of registered residents in the Basic Resident Register Book for Tokyo, as of March 31, 2007. Approximately ten samples were assigned per sampling spot. The primary sampling unit was based on the basic survey units fixed at the 2005 National Census. The sampling spots were sampled from a table of random numbers. Respondents for each sampling spot were selected from the Basic Resident Register Book using a systematic sampling method. Two reserve samples were allotted per respondent. If the primary selected respondent was ineligible, regardless of reason, the reserve samples were used. To ensure adequate sampling of men from the three youngest decades (30-39, 40-49, 50-59), three reserve samples were allotted per respondent. If sampling could not be conducted from the basic resident register book, samples were transferred to a different ward within the same area.