Section 24 Academic Emergency Medicine
24.1 Research methodology
Initiating the research project
The study hypothesis
A hypothesis is a bold statement of what we think the answer to the research question is. Essentially, it is our best guess of what the underlying reality is. As such, it has a pivotal role in any study. The purpose of a research study is to weigh the evidence for and against the study hypothesis. Accordingly, the hypothesis is directly related to the research question.
The study aims
Just as the research question begs the hypothesis, the hypothesis begs the study aims. The examples above demonstrate clearly the natural progression from research question through to the study aims. This is a simple, yet important, process and time spent defining these components will greatly assist in clarifying the study’s objectives. These concepts are discussed more fully elsewhere.1,2
Assembling the research team
All but the smallest of research projects are undertaken as collaborative efforts with the co-investigators each contributing in their area of expertise. Co-investigators should meet the criteria for co-authorship of the publication reporting the study’s findings.3
Usually, the person who has developed and wishes to answer the research question takes the role of principal investigator (team leader) for the project. Among the first tasks is to assemble the research team. Ideally, the principal investigator determines the areas of expertise required for successful completion of the project (e.g. biostatistics) and invites appropriately skilled personnel to join the team.1 It is advisable to keep the numbers within the team to a minimum. In most cases, three or four people are adequate to provide a range of expertise without the team becoming cumbersome. It is recommended that nursing staff be invited to join the team, if this is appropriate. This may foster research interest among these staff, improve departmental morale and may greatly assist data collection and patient enrolment.
Development of the study protocol
The protocol is the blue print or recipe of a research study. It is a document drawn up prior to commencement of data collection that is a complete description of study to be undertaken.4 Every member of the study team should be in possession of an up-to-date copy. Furthermore, an outside researcher should be able to pick up the protocol and successfully undertake the study without additional instruction.
Purpose of the study protocol
Research protocols are required:
Protocol structure
The protocol should be structured largely in the style of a journal article’s Introduction and Methods sections.4 Hence, the general structure is as follows:
Methods
Study design
Study design, in its broadest sense, is the method used to obtain data to prove or disprove the study hypothesis. Many factors influence the decision to use a particular study design and each design has important advantages and disadvantages. For a more extensive discussion on study design the reader is referred elsewhere.1,5
Observational studies
Experimental studies
Types of clinical trials
Concepts of methodology
Validity and repeatability of the study methods
Two types of validity are described:
Study endpoints
Study endpoints are variables that are impacted upon by the factors under investigation. It is the extent to which the endpoints are affected, as measured statistically, that will allow us to accept or reject the hypothesis. For example, a researcher wishes to examine the effects of a new anti-hypertensive drug. It is known that this drug has minor side effects of impotence and nightmares. A study of this new drug would have a primary endpoint of blood pressure drop and secondary endpoints of the incidence of the known side effects.
Sampling study subjects
There are several important principles in sampling study subjects:
Sampling methodology
Stratified sampling
Data-collection instruments
Surveys
Bias and confounding
Study design errors
In any study design, errors may occur. This is particularly so for observational studies. When interpreting findings from an observational study, it is essential to consider how much of the association between the exposure (risk factor) and the outcome may have resulted from errors in the design, conduct or analysis of the study.5 The following questions should be addressed when considering the association between an exposure and outcome:
Systematic error (bias)
Bias in the way a study is designed or carried out can result in an incorrect conclusion about the relationship between an exposure (risk factor) and an outcome (such as a disease) of interest.5 Small degrees of systematic error may result in high degrees of inaccuracy. It is important to note that systematic error is not a function of sample size. Many types of bias can be identified:
Confounding
This is not the same as bias. A confounding factor can be described as one that is associated with the exposure under study and independently affects the risk of developing the outcome.5 Thus, it may offer an alternative explanation for an association that is found and, as such, must be taken into account when collecting and analysing the study results.
Common confounders
In the analysis phase of a study, one can use:
Principles of clinical research statistics
Statistical versus clinical significance
This difference is important for two reasons. First, it forms the basis of sample size calculations. These calculations include consideration of what is thought to be a clinically significant difference between study groups. The resulting sample sizes adequately power the study to demonstrate a statistically and clinically significant difference between the study groups, if one exists. Second, when reviewing a research report, the absolute differences between the study groups should be compared. Whether or not these differences are statistically significant is of little importance if the difference is not clinically relevant. For example, a study might find an absolute difference in blood pressure between two groups of 3 mmHg. This difference may be statistically significant, but too small to be clinically relevant.
Databases and principles of data management
The fundamental objective of any research project is to collect information (data) to analyse statistically and, eventually, produce a result or report. Data can come in many forms (laboratory results, personal details) and is the raw material from which information is generated. Therefore, how data are managed is an essential part of any research project.4
Defining data to be collected
Data entry
Data entry can be achieved in many ways:
Research ethics
If one accepts that clinical trials are morally appropriate, then the ethical challenge is to ensure a proper balance between the degree of individual sacrifice and the extent of the community benefit. However, it is a widely accepted community standard that no individual should be asked to undergo any significant degree of risk regardless of the community benefit involved, that is the balance of risks and benefits must be firmly biased towards an individual participant. According to the Physician’s Oath of the World Medical Association ‘concern for the interests of the subject must always prevail over the interests of science and society’.
Informed consent
Controversies and future directions
1 Taylor DMcD. Practical issues in the design and execution of an emergency medicine research study. Emergency Medicine. 1999;11:167-174.
2 Hall GM, editor. How to write a paper, 2nd edn, London: British Medical Journal Publishing, 1999.
3 Uniform requirements for manuscripts submitted to biomedical journals. Available http://www.jama.ama-assn.org/info/auinst_req.html (accessed March 2002)
4 Good Research Practice Committee. A guide to good research practice. Melbourne: Department of Epidemiology and Preventive Medicine, Monash University, 2001.
5 Jekel JF, Katz DL, Elmore JG, editors. Epidemiology, biostatistics, and preventive medicine, 2nd edn, Philadelphia: WB Saunders, 2001.
24.2 Writing for publication