The validity of aggregated data on alcohol consumption based on self-reports may be particularly biased in studies with short data-collection frames, and caution is required when data on alcohol consumption collected in a short time-frame are compared with other data.
A regression model based on measured data should be able to predict energy performance of a building for a given day as long as the weather conditions are similar to those during the data collection time frame.
Approximately one-fourth of the target population had comprehensive oral examination data available during the 5-year data collection time frame.
Studies were described according to the country of data collection, sampling frame, sample size, response rate, sex, age, the type of outcome and outcome ascertainment.
Further sensitivity analyses that restricted the analytical sample to only the 7,156 subjects who resided in the study area for ≥1 year during the data collection time frame yielded nearly identical results (data not shown).
The Delphi panel size of at least 8 respondents was in line with recommendations that the membership number be relevant to the purpose of the study, the selected design, and data collection time frame [ 12, 13].
Using convenience sampling [ 26], research personnel identified all potential participants presenting to the out-patient department of the hospital within the data collection time frame (January, May and June of 2009).
Other limitations associated with the present study are the inherent bias (over reporting or underreporting) in self-report and the limited data collection time frame for the consumption and drinking frequency of alcoholic beverages.
This strategy also increased the overall data collection time frame as only one researcher was able to attended each school during these visits, which, due to the nature of Chinese weekend cultural schools only running for 3-4 honrs on either a Saturday or Sunday, made attendance at two schools on one day impossible.
