Producing an ISSP data file ready for analysis, involves many different steps and actors. Each year the ISSP General Assembly votes for a Drafting Group whose task it is to develop the questionnaire for the upcoming module. This basic questionnaire is translated within the ISSP member countries to their local language(s) and fielded in time to meet the deposit deadlines. After harmonization and data integration the GESIS Data Archive publishes the international dataset.
Social Inequality V, ISSP 2019
(due to COVID-19, deadlines were postponed by one year, so releases will probably be delayed)
In the course of each annual ISSP General Meeting the General Assembly, consisting of delegates from each member country, selects a topic for ISSP modules with a lead time of three years. By and from their ranks the General Assembly elects a Drafting Group to be in charge of conceptualizing a basic module questionnaire designed to be self-completed by respondents.
In a stepwise process the Drafting Group plans the new module and runs a pretest with focus on the newly implemented or revised items. The General Assembly concludes the design phase of an ISSP module by deciding on the basic questionnaire roughly a year before the module is fielded. Module topics are repeated at agreed intervals. For a module to qualify as a replication, two-thirds of the items must be taken from one or more of the previous questionnaires of that topic module. The remaining third gives the ISSP the chance to include new items on actual topics, relevant for social science research or revise items, which have turned out to be unsatisfying in whatever respect.
Demographic variables are not part of the basic questionnaire. Since there is no central financing, ISSP surveys often travel piggy back, that means attached to large national surveys. In the past, the demographic variables were asked only once and had the priority to meeting the standard of the national surveys. As a result, they sometimes have been collected quite heterogeneously across countries, depending on the national contexts. By means of standardization, homogeneity has been improved over the years. There are more details on ISSP background variables provided.
ISSP member countries translate the British English basic questionnaire to their local language(s) and field it, usually via fielding agencies, in time to meet the depositing deadlines. For Germany, the GESIS department ‘Monitoring Society and Social Change’ is responsible for the German ISSP surveys.
Information on methodology, such as translation and sampling procedures, can be found in the national Study Descriptions as well as for all countries combined in a final method report. The dataset itself contains only little methodological information. In all ISSP datasets a variable on the data collection mode is included and in the most recent ISSP modules variables indicating the date of the interview are available.
ISSP surveys differ from other social survey programs in a number of aspects. Due to the fact that ISSP surveys often run together with large national surveys, which might be conducted only every second year (but then contain two ISSP modules), the fielding times for a certain module vary quite strongly across countries. Apart from that, there is no central funding for ISSP surveys. Some countries have to apply for grants year after year to conduct the survey, sometimes not successfully. Therefore, even long-time ISSP member countries might miss a survey now and then. ISSP membership relapses when two surveys in a row have not been conducted.
According to the ISSP Working Principles, the data together with all documentation forms must arrive at the GESIS archive by September 1st of the calendar year following the year of the data collection for the respective module. A data set will be regarded as not having been deposited until the complete mandatory documentation has been provided.
All data sets being archived within the deadline are guaranteed to be integrated into the module’s international data file. Country data sets which are not completely deposited by April 15th of the second year after the module's year cannot be included into the final integrated file.
Data deposit composition
All data deposits consist of three core elements: First, the data files themselves, second, a set of documentation materials which allows secondary analysts to fully understand the data down to the level of individual response categories in each participating country and third, a set of documentation materials which helps the ISSP methods committee to monitor compliance with the methodological rules of the ISSP.
- A complete and checked data file in SPSS format: All country data sets must be processed and prepared to match the predefined data set structure for this module before the material is delivered to the GESIS Data Archive for integration and archiving.
- A completed template on Background Variables Documentation: Background variables are a set of predominantly demographic variables, which have to be delivered as mandatory part of the national data sets. In the recent years the background variables underwent a stepwise and profound revision. For each ISSP module there are background variable guidelines providing information on the measurement goals and coding instructions.
- A Study Description, which collects basic information about the field procedures, sampling and weighting.
- Information on National Population Characteristics, describing benchmark distributions of core demographic variables for each country.
- A blank copy of the country's field questionnaire(s).
- The completed Study Monitoring Questionnaire: the entries are used for establishing the Study Monitoring Report.
When dealing with international comparative data, data sets and documentation must be regarded as two sides of the same coin. Even though ISSP members make huge efforts to produce comparable data in each country, there still remains a remarkable amount of country specific peculiarities in the contributions to the final, international data set. These country specific peculiarities have either to be harmonized or, if that is not possible, at least documented, as they provide valuable information for secondary analysts. Therefore, ISSP method groups and the GESIS Data Archive (in its function as ISSP data archive) have developed a set of procedures and instruments for taking care of the technical preparation of national data sets and for the systematic collection of the required documentation. In order to ensure the data quality, various plausibility tests, as well as tests on duplicate records (potential fabricated interviews) are conducted. Data corrections are made in consultation with the principle investigators. Finally, the documentation of this data set for the final release is compiled and a codebook (Variable Report) is produced.
The GESIS Data Archive registers and publishes ISSP data sets along with all relevant documents in a user-friendly way and distributes the ISSP data to the scientific community for secondary data analyses via GESIS-Search. The tab "Research Data" provides for download the integrated data set as well as the mandatory national documentation (Study Descriptions/ Technical Reports, Questionnaires, Background Variable Documentation and Characteristics of National Population), the basic questionnaire and generally a Codebook/ Variable Report.
For each annual module, there are two publication dates:
1. The first release is published about six months after the first data deposit deadline and usually includes data of 20-25 countries.
2. The final release is published four to five months after the second data deposit deadline along with an extensive documentation of the data set on ZACAT. It includes all ISSP countries which have conducted the survey.
Further data releases are only issued by the GESIS Data Archive when there is a vital need in terms of data updates. Late coming countries are integrated as the need arises and resources allow.
The GESIS Online Study Catalogue ZACAT enables online analysis and provides detailed documentations of ISSP data sets on variable level and extensive search facilities.
Study monitoring information is compiled for each module as "ISSP (YEAR) Study Monitoring Report" by the chair of the ISSP Methodology Committee, currently Dominique Joye at FORS, University of Lausanne, Switzerland.