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Thursday 16th July, 14:00 - 15:30 Room: O-106

Coding with ISCO, problems and solutions

Convenor Professor Dominique Joye (University of Lausanne )
Coordinator 1Dr Evi Scholz (GESIS)
Coordinator 2Mrs Cornelia Zuell (GESIS)

Session Details

ISCO is the mostly accepted international standard classification of occupational codings, often used in long-standing high quality cross-national surveys. ISCO serves to classify jobs into a clearly defined set of groups according to the tasks and duties in jobs. Due to the long list of hundreds of categories and definitions reflected in the four digits needed for classification, coding of occupations is a challenging enterprise. While categories are exactly defined and mutual exclusive, coding is difficult due to the unclear or incomplete answers of respondents who are not familiar with ISCO, in particular at the most detailed level. ISCO is used to attribute people in class schema as well as attribute scores describing respondents’ position in society.

The proposed session aims at bringing together national and comparative researchers interested in
- the measurement of occupations (mode, question design, etc.);
- techniques of coding ISCO (automatic coding, semi-automatic coding, manual coding);
- problems of coding ISCO (costs, validity, reliability, etc.);
- alternative occupational ISCO coding (e.g., pseudo-ISCO);
- cross-national issues and links to national classification or national tradition;
- ISCO in longitudinal perspective;
- other methodological aspects related to ISCO coding, including coding and measuring of social position in national contexts.

The core of the discussion will be on ISCO08 but contributions based on ISCO88 or earlier are also wellcome.

Paper Details

1. Field Coding the International Standard Classification of Occupations, ISCO 1988
Dr Juergen H.p. Hoffmeyer-zlotnik (University of Giessen)
Mrs Doris Hess (infas Institute for Applied Social Sciences)
Dr Uwe Warner (Perl)

The International Standard Classification of Occupations (ISCO) aspires to provide a systematic classification of all occupations exercised by the whole civilian working population.
Only 45 % of the occupational data collected could be automatically coded into ISCO. We started a project to code occupational data directly to ISCO in the field during the computer assisted data collection phase. Tests enabled that in three or four steps via a tree structure more than 80 % of all occupational data could be coded into ISCO in the field. An error analysis was possible.

2. Occupational Coding Using the ISCO-08 Classification Scheme: Challenges and Problems
Mrs Cornelia Zuell (GESIS)

Coding of occupational data is a crucial task in surveys. Usually, information on occupations is recorded in open-ended questions on job title, main duties and activities. Coding into ISCO-08 requires the assignment to one of the more than 500 individual 4-digit codes of the scheme. The quality and validity of the resulting variables are often low. In this paper, I will present the results of an experiment where different coding services have coded the same occupational survey data. The aim is to identify systematic differences and to develop coding rules to guarantee a higher coding reliability and

3. Asking for Occupation during the Interview: Experimental Results
Mr Malte Schierholz (Mannheim Centre for European Social Research, University of Mannheim)

Currently, most surveys ask for occupation with open-ended questions. The verbatim responses are coded afterwards, which is error-prone and expensive. When textual answers have a low level of detail, exact coding may be impossible. We improve this process by asking response-dependent questions during the interview. Candidate job categories are predicted with a machine learning algorithm. When chances are high that the forecasted job is correct, the interviewer presents a short list of related jobs to the respondent. We compare the new technique to traditional coding practice and describe and quantify different error sources for both methods.

4. The ISCO 2008 and the new German Classification of Occupations 2010
Dr Britta Matthes (Institute for Employment Research)
Mrs Wiebke Paulus (Federal Employment Agency, Statistics)

The goal of developing a new German Classification of Occupations (KldB 2010) was to create an up-to-date classification of occupations for Germany which on the one hand enables an almost one-to-one linkage to the ISCO 2008 and satisfies the occupation-specific structuring of the German labor market on the other hand. In the presentation we first give a short overview of developing KldB 2010, especially how we ensured the high compatibility to ISCO 2008. Secondly, we suggest how to code information on occupations into KldB 2010 and then convert into ISCO 2008.