original version comprised 33 True-False items. A shortened version, the Strahan–Gerbasi only comprises ten items, but some have raised questions regarding the reliability of this measure. In 1991, Delroy L. Paulhus published the Balanced Inventory of Desirable Responding (BIDR): a questionnaire designed to measure two forms of SDR. This forty-item instrument provides separate subscales for "impression management," the tendency to give inflated self-descriptions to an audience; and self-deceptive enhancement, the tendency to give honest but inflated self-descriptions. The commercial version of the BIDR called "Paulhus Deception Scales (PDS)." Scales designed to tap response styles are available in all major languages, including Italian and German. Techniques to reduce social-desirability bias Anonymity and confidentiality Anonymous survey administration, compared with in-person or phone-based administration, has been shown to elicit higher reporting of items with social-desirability bias. In anonymous survey settings, the subject is assured that their responses will not be linked to them, and they are not asked to divulge sensitive information directly to a surveyor. Anonymity can be established through self-administration of paper surveys returned by envelope, mail, or ballot boxes, or self-administration of electronic survey via computer, smartphone, or tablet. Audio-assisted electronic surveys have also been established for low-literacy or non-literate study subjects. Confidentiality can be established in non-anonymous settings by ensuring that only study staff are present and by maintaining data confidentiality after surveys are complete. Including assurances of data confidentiality in surveys has a mixed effect on sensitive-question response; it may either increase response due to increased trust, or decrease response by increasing suspicion and concern. Specialized questioning techniques Several techniques have been established to reduce bias when asking questions sensitive to social desirability. Complex question techniques may reduce social-desirability bias, but may also be confusing or misunderstood by respondents. Beyond specific techniques, social-desirability bias may be reduced by neutral question and prompt wording. Randomized response techniques The randomized response technique asks a participant to respond with a fixed answer or to answer truthfully based on the outcome of a random act. For example, respondents secretly throw a coin and respond "yes" if it comes up heads (regardless of their actual response to the question), and are instructed to respond truthfully if it comes up tails. This enables the researcher to estimate the actual prevalence of the given behavior among the study population without needing to know the true state of any one individual respondent. Research shows that the