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Table 5 The definition of potential biases as they affect pet ownership studies

From: Methods used to estimate the size of the owned cat and dog population: a systematic review

Type of bias

Definition

Selection bias

Selection bias is a systematic error that occurs when the distribution of factors associated with pet ownership in the target population differs from those in the study population [58].

Non-response bias

Non-response bias is when the characteristics that are associated with pet ownership of respondents differ from the characteristics of those that did not respond [66].

Measurement bias

Measurement bias is caused by inaccurate responses to survey questions which can result in misclassification of pet owners [66].

Length of sampling bias

Biases introduced by length of sampling time are introduced by estimating point prevalence (number of owned pets) over a relatively long sampling time, or by using period prevalence (number of owned pets in a given time period) to estimate point prevalence [86].