You must choose a design that appropriately answers your objective. When you have a finalized protocol or proposal, you will be ready to submit this to your institutional review board or local ethics committee. It is essential that you choose the right methodology to allow you to answer your research question to the best of your ability. Broadly there are the following research methodologies for observational studies:
Methodologies
- Cohort study: Studying a group of people with a shared ‘exposure’. This may be retrospective (for example, you may review a group of participants who have already undergone a particular type of surgery) or prospective (for example, you may follow-up a group of participants who are planning to undergo a particular type of surgery). Prospective studies are generally more informative as you will state the 'outcomes' that you wish to study in advance, therefore reducing the risk of introducing bias into subsequent analyses. They are particularly good for establishing causality due to their temporal nature, as well as identifying the 'rate' or 'incidence' of various outcomes related to an exposure.
- Case control study: Similar to a cohort study, however a 'control' group is also studied for comparison. This group will come from the same population as the group which is subject to your 'exposure' of interest. Case control studies are good for quickly defining the relationship between background variables, exposures, and your chosen outcomes.
- Randomized-controlled trial: a more 'rigorous' form of research that requires prospective recruitment of participants, who are either 'exposed' or 'not exposed' to an intervention of interest. For example, you might compare one drug for overactive bladder to another, or to a placebo. Prospective data collection, pre-stated outcomes and randomization all reduce bias allowing for more meaningful results. These are typically the most resource intense and longest studies to undertake due to the nature of their design, however they also yield the highest quality data.
Outcome measurement
Choosing an outcome measure is a key part of designing your research. An outcome is the result or effect that you will be measuring to determine if an 'exposure' influences your study participant. To ensure standardization of outcomes (allowing for meta-analysis and meaningful comparison), the CROWN initiative is working on agreed outcomes for women's health research. For patient reported outcomes (PROMS), various questionnaires have been assessed for validity by the International Continence Society and can be found in the 'Incontinence' publication.
Other resources for assistance in study design are listed below.
Center for Evidence Based Medicine (University of Oxford) overview of study design
You have got research ideas but you do not know where and how to start - Types of research studies, outcome measurements and their assessment - E-Lecture by Kaven Baessler
Designing Clinical Research, Chapter 3: Choosing the Study Subjects: Specification, Sampling, and Recruitment
Databases
Studies require analysis of data characterizing patients and their outcomes. Collecting data in an organized, systematic fashion is essential. There are many ways to store data. IUGA members have access to a Surgical Data Collection system to track their own outcomes.
Existing datasets are available which compile information from multiple institutions, professional organization members, or national registries. Existing datasets can provide a large sample with extensive information to characterize patients and measure outcomes. IUGA members can access the IUGA surgical database for opportunities to use a larger dataset.
Ethics and Institutional Review Boards
Before initiating your study, it’s essential to check with your institutional board to make sure you have approval to proceed. Globally, disseminated research should have a statement regarding approval from an institutional or ethics review board (or a statement of exemption from review). The requirements and rigor of review may differ by region or institution.
There are papers and checklists that provide recommendations for ensuring quality in your study design. Review of these guidelines and checklists is recommended prior to initiating your study.
Guideline Papers and Quality Checklists
Note: Before embarking on the process of obtaining ethical approval, first check if it is needed as for some retrospective studies, registration at your hospital as an 'audit' may be all that is necessary.
Registration of your Study: Avoid Duplication
Designing and conducting a study is a great deal of work. Registering your study helps to avoid duplication. Registration can be done at many stages, but ideally is done prior to study initiation. Ethics/Institutional review boards may want to know if this is a registered study and registration information may be included during the informed consent process.
Here are examples (not an all-inclusive list) of registries across the world. Search for the registry that is most appropriate for your study design and region.
International Prospective Register of Systematic Reviews (PROSPERO)
Australian New Zealand Clinical Trials Registry (ANZCTR)
Australasian Pelvic Floor Procedure Registry (APFPR)
National Institutes of Health US National Library of Medicine