As in all surveys, the possibility of errors and the limitations of the survey, its instrument, and the manner in which it is distributed, must be taken into account when interpreting a survey's results. These were minimized for this survey by a pre-testing conducted at The Search Institute, specialized training of people who administered the survey, coding checks when completed questionnaires were scanned, and checks of quality control. Where the survey team suspects nonsampling errors, these have been noted in this report. In other words, the reported current use of a particular drug may vary slightly from one sample to the next, because of the natural differences which exist in people, their location, social practices, etc. For example, people in the far southern end of the state may have slightly different rates of particular behaviors than people in the extreme northwest corner of the state, and the state-wide results may not reflect an accurate picture of the rates throughout the state if disproportionate numbers of people are sampled in the south relative to the northwest portion of the state.
Scientists often use statistical formulas to calculate an estimate of the amount of sampling error.
However, since all of the 31 surveys aggregated for this study individually used entire populations, rather than population samples, and since the 31 surveys are not scientifically selected, it would be inappropriate to report estimates of sampling error, since this is unknown for our population. In addition, self-reporting depends on accuracy of memory and honesty in answering questions. The survey uses several error-checking protocols, including checks for consistency, biological plausibility, and a decoy question about a fictitious drug, to identify potential problem cases, which were removed from analysis. Due to the fact that data were not collected in all communities during the same sampling time frame, certain measures that are time-sensitive may be biased. Eleven of the surveys were conducted during the spring semester of 1999, and 20 surveys were conducted during the fall semester of 1999.