Analysis of hospital admissions may have been affected by the different data collection periods at baseline and follow-up and consideration of adjustments for multiple testing.
By using different data collection procedures, the researcher is able to increase the validity and robustness of results because the findings can be strengthened by cross validation achieved by using data obtained through different strategies [ 37].
Triangulation by using different data collection techniques, i.e. in-depth interview and FGD, along with the use of multiple interviewers and different categories of participants increases the validity of the results [ 36, 41].
Experience has shown that integrated studies are often limited by the lack of data, or by the fact that different data collection systems have different goals and are, therefore, not easily combined.
In this study, credibility was ensured by triangulation which used different data collection strategies, including field notes, group interviews and individual interviews, 30 and involved a range of participants at different sites.
To our knowledge, this issue has not been investigated in the occupational exposure literature, and so the accuracy and precision of variance components derived by standard procedures under different data collection scenarios are only superficially understood.
This discrepancy could perhaps be explained by the fact that different data collection methods were utilised; the MNCAH policy surveys rely on national authorities to report to the WHO, whereas the every newborn consultation utilised a more qualitative approach.
Validation of findings was done by triangulating information from the different data collection methods.
In practice, different data collection mechanisms are used by different transport operators, depending on the nature of their business.
