Authors: O. M. Olayiwola, G.N. Amahia, A.A. Adewara

Journal of Mathematics Research

Abstract

When a selected sample member refuses to take part in a survey interview, the survey organization may not accept the refusal as a final outcome, but rather to make further attempts to convert the refusals into an interview.  The aim of this study was to investigate the pattern of refusals conversion and the propensity of the converted refusals to respond at later waves in a longitudinal survey.

A two-stage stratified randon sampling scheme was used with households in Oyo as the sampling unit. A sample of 750 households were randomly selected from the community and sub-divided into five equal groups with each group treated as a wave. The recording schedule was used to obtain information on demographic characteristics including survey process, external environment, age, gender, educational qualification, religion, employment status, family size, duration of interview and the type of questions. The data were collected through oral interview of the subjects. Summary statistics were constructed to look at the patterns of conversion of refusals. Logistic model was fitted to investigate the propensity of converted refusals to respond at later waves following a conversion. At wave 1 of the survey, 109 house heads were interview in households with a response rates (in percentage) of 72.67.The interview period was an average of 8 minutes per house head. The response rate at wave 2, wave 3, wave 4 and wave 5 were 82, 81.33, 82 and 80.67 respectively. Outcomes of a conversion attempt were a full interview and a proxy interview. Five house heads went through the conversion process at wave 1 and data were successfully collected on 2 of them (40%). All of them were interviewed again at wave 2 (100%). Those converted refusals at wave 1, 100% gave a full interview six months later. For house heads who were converted between wave 1 and wave 5 continued to give full interviews at every wave up to wave 5. For all other waves, the converted refusals participated throughout the survey. Logistic model showed that, those who were converted to a full interview rather than proxy interview were the most likely to give a full interview at subsequent wave.  When we included in the model, information on the wave in which the initial conversion was took place and the time since conversion, we found that those whose initial conversions were in earlier and later waves were less likely to give a full interview compared with those were converted at wave 3.Adding demographic information suggested that male, people with their ages between ((30 – 50) years, respondents with primary education were likely to take part again following a conversion.

 

 

Keywords: Converted refusals, Logistic model, Longitudinal survey, Wave, Propensity