Blogs: Study Introduction: The Korean Longitudinal Study of Aging (KLoSA)

Study Introduction: The Korean Longitudinal Study of Aging (KLoSA)

by Hae Yeun Park
May 03, 2021

The Korean Longitudinal Study of Aging (KLoSA) is a panel study of people over age 45, living in South Korea. A nationally representative sample was initially recruited in 2006 for the first wave, and a refreshment sample was added in 2014 for the fifth wave. A core survey is conducted every even-numbered year starting from 2006, and Waves 1 – 7 have been released so far. To make it easier to conduct cross-country comparative studies on ageing, the survey is designed to be comparable with the Health and Retirement Survey (HRS) in the United States, the Survey of Health, Ageing and Retirement in Europe (SHARE) in continental Europe, and the English Longitudinal Study of Ageing (ELSA) in England. Topics of the survey include demographics, family structure, health, employment, income, assets, and life satisfaction.

In order to make the survey more accessible, the USC Gateway to Global Aging team created the Harmonized KLoSA, a user-friendly version of a subset of the KLoSA. In order to facilitate cross-national analyses with the other Gateway Harmonized datasets – Harmonized datasets for the HRS (USA), MHAS (Mexico), ELSA (England), SHARE (Europe and Israel), CRELES (Costa Rica), JSTAR (Japan), TILDA (Ireland), CHARLS (China), LASI (India), and MARS (Malaysia) – all follow the same standards for variable naming and data structure. Users can easily create the Harmonized KLoSA data using the Harmonized KLoSA creation code. The recently released version D of the Harmonized KLoSA now incorporates up to Wave 7.

The KLoSA and the Harmonized KLoSA can be analyzed by itself and/or together with the other HRS-family datasets for cross-national analyses. In order to check what topics and variables are available and comparable with the other studies, users can use concordance tables to search for topics and variables of interest. For instance, one might find it useful to utilize newly added information (in Wave 5 through 7) that are relevant to long-term care insurance, which are shown in Figure 1.

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Fig 1. Concordance tables - utilize newly added information that are relevant to long-term care insurance

One advantage of the Harmonized KLoSA is that it distinguishes variables by a suffix, “_K”, if the variables are Harmonized KLoSA specific. The suffix indicates that there are significant differences between the RAND HRS/Harmonized HRS and the Harmonized KLoSA measures, implying direct comparison of these variables would not be straightforward. These differences include cases such as differences in survey questions and differences in scales used. For example, the Harmonized KLoSA variable for labor force status is RwLBRF_K rather than RwLBRF because the variable is derived from different survey questions and it uses a slightly different categorization compared to the RAND HRS variable RwLBRF. While it is strongly recommended for users to check the “Differences with the RAND HRS/Harmonized HRS” section of each measure before comparing variables from different surveys, the “_K” suffix helps users to notice differences at a glance. Moreover, the Harmonized KLoSA-specific variables may be particularly useful to those who are interested in population aging in South Korea, as the variables generally contain information specific to the South Korean context and culture.

We are also pleased to announce a new release of harmonized data for KLoSA including a new End of Life dataset. Visit the Gateway to Global Aging Data download page for the codebooks and the creation codes. We also recently hosted a webinar discussing the study design and data structure of the newly released harmonized data. A recording of the session can be found here and the presentation slides can be found here. Please check back often for updates to the Harmonized KLoSA!

about the author
Hae Yeun Park is a Research Assistant for The Program for Global Health, Aging & Policy at the Center for Economic and Social Research at the University of Southern California.