This module provides the basic knowledge needed to conduct practice-based clinical research. It introduces evidence-based optometry which involves learning how to ask answerable research questions, conduct literature searches on electronic databases and critically evaluate scientific publications. Epidemiology is defined followed by an explanation of how to decide upon which study design is most likely to answer the research question. The advantages and disadvantages of cross-sectional studies, case-control studies, cohort studies and randomized-controlled clinical trials are discussed in terms of their susceptibility to bias and other forms of data distortion. Qualitative research, questionnaire studies, meta-analysis and decision analysis are introduced.
Differences between discrete and continuous data are explained in the context of deciding whether to use parametric or non-parametric statistical tests to analyse results. This involves learning about the normal distribution and how to select the correct measures of central tendency (mean, mode and median) and dispersion (standard deviation, coefficient of variation, standard error of the mean, confidence limits, range and interquartile range). The calculation of relative risks and odds ratios, together with their respective confidence limits, as a means of assessing disease risk in epidemiological studies is also explained.
Evaluation of diagnostic tests is covered in terms of assessing discriminative ability (sensitivity, specificity, predictive values and likelihood ratios, ROC curves), validity and repeatability (Bland-Altman plots, coefficient of variation, kappa).
Five lectures are devoted to hypothesis testing and cover testing normality (Kolmogorov-Smirnov one-sample test), the comparison of two (t-tests, Mann-Whitney U test, Wilcoxon signed-rank test) or more (analysis of variance, Kruskal-Wallis test, Freidman test) groups, correlation (Pearson, Spearman and Kendall correlation coefficients), linear regression (slope, intercept, coefficient of determination) and analysis of frequencies (Chi-square goodness of fit and contingency tests, Yates’ correction, Fisher’s exact test, phi coefficient). Descriptions are provided for performing these epidemiological and statistical calculations using SPSS and Microsoft Excel.
Finally, clinical research ethics covers landmark documents (The Nuremberg Code, Declaration of Helsinki, Belmont Report and International Ethical Guidelines for Biomedical Research Involving Human Subjects), key ethical theories (consequentialist, deontology, virtue ethics), laws protecting research participants (Data Protection Act, EU Clinical Trials Directive, Human Tissues Act and the Mental Capacity Act), NHS ethics (NRES, IRAS), University ethics and preparation of a research protocol and consent form for ethical approval.
Areas covered will include:
- An introduction to evidence-based optometry
- Research design and the investigation of cause and effect
- Normal distribution, central tendency and dispersion
- Assessment of risk in epidemiological studies and evaluation of diagnostic techniques
- Hypothesis testing I: Testing normality and comparing the means of two groups
- Hypothesis testing II: Comparing the means of more than two groups (Analysis of variance)
- Hypothesis testing III: Correlation
- Hypothesis testing IV: Linear regression
- Hypothesis testing V: Analysis of frequencies
- Clinical research ethics