A high response is not essential to prevent selection bias: results from the Leiden 85-plus study

A Bootsma-van der Wiel, E van Exel, A J M de Craen, J Gussekloo, A M Lagaay, D L Knook, R G J Westendorp

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

We tested the hypothesis that an additional effort to increase the response rate would diminish selection bias in a community-based cohort study. In the Leiden 85-plus Study, all subjects of the town of Leiden who had reached their 85th birthday were informed of the study by mail and then asked to participate by telephone. In an additional recruitment stage, those subjects who did not participate directly were visited and personally asked to participate. When these subjects refused, some nonresponse questions were asked. In this way we collected data on the whole source population. Of 691 eligible elderly subjects, 511 subjects (74%) participated directly. Of those who did not participate directly, 88 subjects participated after the additional effort. The response rate increased from 74% to 87%. Compared to the 511 subjects who directly participated, the 88 subjects who entered the study after the additional effort had poorer health and lower survival. The subjects who refused were more healthy and had poorer mood. The direct sample did not differ from the source population with respect to socio-demographics, health, and mortality. In conclusion, we showed that given a moderately high direct response the additional effort was effective in increasing the response rate, but was also selective and was not necessary to prevent selection bias.

Original languageEnglish
Pages (from-to)1119-25
Number of pages7
JournalJournal of Clinical Epidemiology
Volume55
Issue number11
Publication statusPublished - Nov 2002

Cite this

der Wiel, A. B., van Exel, E., de Craen, A. J. M., Gussekloo, J., Lagaay, A. M., Knook, D. L., & Westendorp, R. G. J. (2002). A high response is not essential to prevent selection bias: results from the Leiden 85-plus study. Journal of Clinical Epidemiology, 55(11), 1119-25.
der Wiel, A Bootsma-van ; van Exel, E ; de Craen, A J M ; Gussekloo, J ; Lagaay, A M ; Knook, D L ; Westendorp, R G J. / A high response is not essential to prevent selection bias : results from the Leiden 85-plus study. In: Journal of Clinical Epidemiology. 2002 ; Vol. 55, No. 11. pp. 1119-25.
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abstract = "We tested the hypothesis that an additional effort to increase the response rate would diminish selection bias in a community-based cohort study. In the Leiden 85-plus Study, all subjects of the town of Leiden who had reached their 85th birthday were informed of the study by mail and then asked to participate by telephone. In an additional recruitment stage, those subjects who did not participate directly were visited and personally asked to participate. When these subjects refused, some nonresponse questions were asked. In this way we collected data on the whole source population. Of 691 eligible elderly subjects, 511 subjects (74{\%}) participated directly. Of those who did not participate directly, 88 subjects participated after the additional effort. The response rate increased from 74{\%} to 87{\%}. Compared to the 511 subjects who directly participated, the 88 subjects who entered the study after the additional effort had poorer health and lower survival. The subjects who refused were more healthy and had poorer mood. The direct sample did not differ from the source population with respect to socio-demographics, health, and mortality. In conclusion, we showed that given a moderately high direct response the additional effort was effective in increasing the response rate, but was also selective and was not necessary to prevent selection bias.",
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der Wiel, AB, van Exel, E, de Craen, AJM, Gussekloo, J, Lagaay, AM, Knook, DL & Westendorp, RGJ 2002, 'A high response is not essential to prevent selection bias: results from the Leiden 85-plus study' Journal of Clinical Epidemiology, vol. 55, no. 11, pp. 1119-25.

A high response is not essential to prevent selection bias : results from the Leiden 85-plus study. / der Wiel, A Bootsma-van; van Exel, E; de Craen, A J M; Gussekloo, J; Lagaay, A M; Knook, D L; Westendorp, R G J.

In: Journal of Clinical Epidemiology, Vol. 55, No. 11, 11.2002, p. 1119-25.

Research output: Contribution to journalArticleAcademicpeer-review

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T1 - A high response is not essential to prevent selection bias

T2 - results from the Leiden 85-plus study

AU - der Wiel, A Bootsma-van

AU - van Exel, E

AU - de Craen, A J M

AU - Gussekloo, J

AU - Lagaay, A M

AU - Knook, D L

AU - Westendorp, R G J

PY - 2002/11

Y1 - 2002/11

N2 - We tested the hypothesis that an additional effort to increase the response rate would diminish selection bias in a community-based cohort study. In the Leiden 85-plus Study, all subjects of the town of Leiden who had reached their 85th birthday were informed of the study by mail and then asked to participate by telephone. In an additional recruitment stage, those subjects who did not participate directly were visited and personally asked to participate. When these subjects refused, some nonresponse questions were asked. In this way we collected data on the whole source population. Of 691 eligible elderly subjects, 511 subjects (74%) participated directly. Of those who did not participate directly, 88 subjects participated after the additional effort. The response rate increased from 74% to 87%. Compared to the 511 subjects who directly participated, the 88 subjects who entered the study after the additional effort had poorer health and lower survival. The subjects who refused were more healthy and had poorer mood. The direct sample did not differ from the source population with respect to socio-demographics, health, and mortality. In conclusion, we showed that given a moderately high direct response the additional effort was effective in increasing the response rate, but was also selective and was not necessary to prevent selection bias.

AB - We tested the hypothesis that an additional effort to increase the response rate would diminish selection bias in a community-based cohort study. In the Leiden 85-plus Study, all subjects of the town of Leiden who had reached their 85th birthday were informed of the study by mail and then asked to participate by telephone. In an additional recruitment stage, those subjects who did not participate directly were visited and personally asked to participate. When these subjects refused, some nonresponse questions were asked. In this way we collected data on the whole source population. Of 691 eligible elderly subjects, 511 subjects (74%) participated directly. Of those who did not participate directly, 88 subjects participated after the additional effort. The response rate increased from 74% to 87%. Compared to the 511 subjects who directly participated, the 88 subjects who entered the study after the additional effort had poorer health and lower survival. The subjects who refused were more healthy and had poorer mood. The direct sample did not differ from the source population with respect to socio-demographics, health, and mortality. In conclusion, we showed that given a moderately high direct response the additional effort was effective in increasing the response rate, but was also selective and was not necessary to prevent selection bias.

KW - Activities of Daily Living

KW - Affect

KW - Aged

KW - Aged, 80 and over

KW - Cognition

KW - Female

KW - Follow-Up Studies

KW - Frail Elderly/statistics & numerical data

KW - Geriatric Assessment/methods

KW - Health Status

KW - Health Surveys

KW - Humans

KW - Male

KW - Netherlands/epidemiology

KW - Selection Bias

KW - Socioeconomic Factors

KW - Survival Rate

M3 - Article

VL - 55

SP - 1119

EP - 1125

JO - Journal of Clinical Epidemiology

JF - Journal of Clinical Epidemiology

SN - 0895-4356

IS - 11

ER -

der Wiel AB, van Exel E, de Craen AJM, Gussekloo J, Lagaay AM, Knook DL et al. A high response is not essential to prevent selection bias: results from the Leiden 85-plus study. Journal of Clinical Epidemiology. 2002 Nov;55(11):1119-25.