1997 Sep-Oct;26(5 Pt 1):674-7. doi: 10.1006/pmed.1997.0189. Readers of medical studies should understand the different implications of these uses to improve their critical evaluation of studies. However, qualitative research has the benefit of being flexible and allowing creativity; thereby providing additional insights that cannot be collected through quantitative research.What then are the types of biases faced by qualitative researchers? The investigator essentially induces selection bias to enable efficient control of confounding. Conducting research is the first and most exciting step in a researcher's journey. While matching alone does not address confounding in case–control studies, it does guarantee that there will be a balanced number of cases and controls within strata of the matching factors to permit efficient statistical adjustment for those factors. Selection bias occurs when participation in a study is jointly influenced by exposure and disease status. Bias, defined as the “inclination or prejudice for or against one person or group, especially in a way considered to be unfair,” can be extremely detrimental to scientific progress as it can lead to the distortion of reality and thereby affect the validity and reliability of research findings. Qualitative research is an exploratory scientific method of observation to gather non-numerical data. Avoidance of bias in the first of these issues, selection of representative subjects, enhances the ability to generalize a study's results. Perhaps the most well-known example of selection bias is the confirmation bias, whereby people tend to recall only examples that confirm their existing beliefs. In case–control studies, selection bias occurs when selection of controls is not independent of exposure. Once you understand and identify the different types of biases, it will become easier to take measures to avoid them as well.Broadly, biases can be of two types – participant bias and researcher bias. So you should not give away any details about the sponsors such as the company logo or provide your role or the goal of the study.Consider all the data obtained and analyse it with a clear and unbiased mind. Selection bias is the bias introduced by the selection of individuals, groups or data for analysis in such a way that proper randomization is not achieved, thereby ensuring that the sample obtained is not representative of the population intended to be analyzed. This will help the participant to project his or her own feelings onto others and provide accurate, truthful, and more representative answers.Ensure that different questions are worded differently and that the questions are engaging throughout the interview.It is important for you, as researchers, to maintain neutrality so as to not influence the participants’ responses. On the other hand, bias from a researcher’s end may get introduced if researchers unknowingly interpret data to meet their hypothesis or include only data that they think are relevant. The practice of matching in case–control studies illustrates … There are many types of possible selection bias, including: Do not use leading questions that can prompt the participant to respond in favour of a particular assumption.While research that is completely unbiased is ideal, it may not always be possible. 30 Once selection bias occurs not much can be done, but sensitivity analyses can be performed.To correct the bias, as such, it is especially important to ensure that selection bias is avoided when recruiting and retaining the sample population. Selection/participant bias Selection bias relates to both the process of recruiting participants and study inclusion criteria. Selection bias is defined as a nonrandom imbalance among treatment groups of the distribution of factors capable of influencing the end points—that is, of subexperimental factors (including prognostic factors).where the denominator of the expression is introduced to make the density In many problems in economics, attention focuses on From a sample of data, it is not possible to recover the true density and by hypothesis both the numerator and denominator of the left-hand side are known, and ∫ Selection bias occurs early on in epidemiology study during the recruitment of participants and subsequently in the process of retaining the participants for the duration of the study.