Reliability -- Research Starters Sociology

Description

To yield useable data, surveys, assessment tools, and other data collection instruments need to be both reliable and valid. Reliability is a measure of the degree to which such instruments consistently measure a characteristic or attribute. Statistically, reliability is a measure of the observed variability in obtained scores on an instrument. Variability can come both from true variance (such as differences in opinions, knowledge, or other characteristics of the individual) or from error variance. The total variability of a data collection or assessment instrument is the sum of the true variability and the variability due to error. Reliability can be estimated through the use of parallel forms of the instrument, repeated administration of the same form of the instrument, subdivision of the instrument into two parallel groups of items, and analysis of the covariance among the individual items.