Acquiescence bias, also known as agreement bias,[1] is a category of response bias common to survey research[2] in which respondents have a tendency to select a positive response option[1][3] or indicate a positive connotation disproportionately more frequently.[2][4][5] Respondents do so without considering the content[3] of the question or their 'true' preference.[1] Acquiescence is sometimes referred to as "yea-saying" and is the tendency of a respondent to agree with a statement when in doubt. Questions affected by acquiescence bias take the following format: a stimulus in the form of a statement is presented, followed by 'agree/disagree,' 'yes/no' or 'true/false' response options.[2][6] For example, a respondent might be presented with the statement "gardening makes me feel happy," and would then be expected to select either 'agree' or 'disagree.' Such question formats are favoured by both survey designers and respondents because they are straightforward to produce and respond to.[3][6] The bias is particularly prevalent in the case of surveys or questionnaires that employ truisms as the stimuli, such as: "It is better to give than to receive" or "Never a lender nor a borrower be". Acquiescence bias can introduce systematic errors that affect the validity of research by confounding attitudes and behaviours with the general tendency to agree, which can result in misguided inference. [2] Research suggests that the proportion of respondents who carry out this behaviour is between 10% and 20%.[2]