Pharmacoepidemiology: Evaluating Study Design Bias in Research Methods

This report provides an analysis of how different study designs in pharmacoepidemiology are susceptible to various types of bias. It discusses three primary study types: cohort studies, case-control studies, and cross-sectional studies, and ranks them based on their vulnerability to selection bias, classification bias, confounding bias, and information bias. The report highlights that cohort studies are susceptible to selection and misclassification biases, case-control studies are affected by selection and information biases due to differential selection and misclassification of exposure status, and cross-sectional studies are vulnerable to non-response bias, which affects the reliability of outcome measurements. The analysis emphasizes the importance of understanding these biases to improve the validity and reliability of pharmacoepidemiological research.

Running head: HOME EXERCISE ASSIGNMENT
RESEARCH PROCESS AND ASSOCIATED BIASES
Name of the Student
Name of the University
Author note

1HOME EXERCISE ASSIGNMENT
Study bias in defined as a systematic error that occurs due to the presence of errors in
investigation process and distorted calculations [1]. This is a limiting factor for any research
study as due to the presence of study bias the reliability of the study reduced and validity of the
intervention reduced depending on the degree of the error. There are primarily three type of
biases, such as confounding bias, selection bias, and information bias [2]. This section discusses
about the effect of errors on different study types such as cohort study, case control study and
cross sectional study and their susceptibility to be exposed to each type of individual bias. The
following ranking has been done depending on the susceptibility of each research process.
Cohort study
Cohort study is conducted in the research process to identify the subject group for their
risk of specific disease or any other condition, understanding the exposure status of each
individual in that experiment and to observe the healthcare outcomes for all the patients during
the proposed timeline. This is an effective research approach however; several biases could
affect the analysis of the process [1]. These bias included selection, classification and
confounding bias. Susceptibility to selection bias occurs to the presence of bias in the selection
of cohort population, loss of follow ups and non-responsive data collection and inclusion of
prevalent population, who already were suffering from subject disease [3]. Further,
misclassification errors occur due to the presence of incorrect classification of the exposure
and/or disease status of study participants. Therefore, these are the biases that affected this study
approach.
Case control study

2HOME EXERCISE ASSIGNMENT
Case control study is determined as a study design that builds the relationship between
the disease and one of more preventive factor as the selection of the people base on their disease
condition and people who are not affected with the disease and then comparison is drawn in
terms of their exposure to the factors under study [3]. Bias that could affect the reliability of the
study is information bias and the study bias. Selection bias occurs in the case control study as the
cases and control group are selected differentially on the basis of their exposure status. It is also
seen that the differences in reporting of exposure status between cases and controls [2]. Further,
due to the difference between the exposure of the case, bias occurred in the research process.
Further informative bias occurs in the case control study because the case and the control group
are misclassified and the measurements of variables are not done properly [4].
Cross-sectional study
Cross-sectional researches gather data between a selected time period due to which
researchers are able to assess the prevalence of a disease or of other variables of interest [3]. The
bias associated to cross sectional study is the non-responsive nature of the participants which is a
particular problem affecting cross-sectional researches and which can result in the bias of the
measurement of outcomes. Due to this bias, it becomes difficult to understand the exposure time,
resulted in the outcome witnessed and affecting the reliability of the research process [4].

3HOME EXERCISE ASSIGNMENT
References
1. Hadi M, José Closs S. Ensuring rigour and trustworthiness of qualitative research in clinical
pharmacy. International Journal of Clinical Pharmacy Published Online First: 2015.
doi:10.1007/s11096-015-0237-6
2. Noble H, Smith J. Issues of validity and reliability in qualitative research. Evidence-based
nursing. Published Online First: 2015 Apr 1;18(2):34-5.DOI: https://doi.org/10.1136/eb-2015-
102054
3. Smith J, Noble H. Bias in research. Evidence-based nursing. Published Online First: 2014 Oct
1;17(4):100-1.DOI: 10.1136/eb-2014-101946.
4. Queirós A, Faria D, Almeida F. Strengths and limitations of qualitative and quantitative research
methods. European Journal of Education Studies. Published Online First: 2017 Sep 7.Retrived
from: https://oapub.org/edu/index.php/ejes/article/view/1017