Sampling

The information on sports participation is taken from the NSGA research study 'Sports Participation in 2007.' For this study, a mail panel resource of more than 300,000 pre-recruited households was used. The panel is balanced on a number of characteristics determined to be key indicators of general purchase behavior, including household size and composition, household income, age of household head, socio-economic status of the household, and region and market size.

During the first week of February 2008, a self-administered questionnaire was mailed to 10,000 of these households. The sample is balanced to oversample lower 'return rate' segments to yield a return sample which is correctly representative of the continental United States based upon these characteristics.

Questionnaire

The questionnaire asked the male and female heads of households and up to two other household members who were at least seven years of age to indicate their age, the sports in which they participated in 2007, and the number of days of participation in 2007. The sports included those listed in the accompanying tables.

Participants

A participant is defined as an individual seven years of age or older who participates in a sport more than once a year for all sports except aerobic exercising, bicycle riding, exercise walking, exercising with equipment, running/jogging, step aerobics, swimming and weightlifting. For these seven fitness sports, participation is defined as six times or more during the year.

Statistical Notes

In basing estimates of a population on a sample drawn from that population, a degree of sampling error is possible. While a number of biases can affect the extent of sampling error, it is to a great degree dependent on the size of the sample. The larger the sample, the more closely the estimate represents to total population.

Sampling error also affects samples of the same size. A sample drawn from a population will result in an estimate for a characteristic of the population, the proportion of aerobics exercisers for example. If another sample were drawn, it would include different members of the population. This would yield a slightly different estimate of the proportion of aerobics exercisers.


To allow judgments and decisions to be made with confidence when using samples, we can determine a confidence interval for the estimate.

A confidence interval is simply a range. A 95% confidence interval for the proportion of archers in the population is a range in which the estimates for the proportion of archers would fall 95% of the time, were the study to be done repeatedly. For example, in a particular year, the proportion of respondents who stated they participated in archery was 1.9% (after weighting and projection). Thus, if we were to estimate the proportion of archers in the United States using 100 similar studies, 95 of those studies would yield an estimate within 95% confidence interval of 1.8%-2.0% (+/0.1%) from the stated proportion.

Additional Information

More detailed information on the sports in the survey is available from the NSGA Research Department. For information on the reports available, their contents and costs, access our online order form.