INTRO TO RESEARCH METHODS AND STATISTICS - LEARNING OUTCOMES Flashcards
Describe how you would go about defining a research questions for further study.
Whatever form a research question takes, it needs to be well-defined. One useful way of focussing a research question is to use the PICO approach:
People, patients or population – who are you asking the question about?
Intervention – what intervention are you interested in?
Control or comparison – what are you comparing the intervention to?
Outcome – what outcome are you interested in measuring?
This is mainly applicable to quantitative research questions.
Describe ways of defining disease for a research study.
For clinical medicine a patient tends to either be categorised as sick or healthy.
The ways in which individual diseases are defined and diagnosed tend to fit into the clinical, statistical, prognostic and operational categories.
Clinical disease definition is based on the recognition of a characteristic pattern of history, current symptoms and physical signs on examination, often supplemented by data from clinical investigation.
The statistical method of defining disease is in terms of a particular attribute or objective measurement value that lies outside of a defined normal range. This is the standard practice in the definition of abnormal results in many laboratory investigations in which 5% or the population are arbitrarily defined as abnormal.
A prognostic definition involves defining a disease in terms of a measurement, clinical finding, laboratory test result or other characteristic that carries prognostic significance.
Operational definitions of disease are based on the identification of individuals in whom a different management or treatment policy is indicated – for example hypertension is now defined operationally as the level above which therapy is given.
Give a clinical definition of disease.
Clinical disease definition is based on the recognition of a characteristic pattern of history, current symptoms and physical signs on examination, often supplemented by data from clinical investigation.
Give a statistical definition of disease.
The statistical method of defining disease is in terms of a particular attribute or objective measurement value that lies outside of a defined normal range. This is the standard practice in the definition of abnormal results in many laboratory investigations in which 5% or the population are arbitrarily defined as abnormal.
Give a prognostic definition of disease.
A prognostic definition involves defining a disease in terms of a measurement, clinical finding, laboratory test result or other characteristic that carries prognostic significance.
Give an operation definition of disease.
Operational definitions of disease are based on the identification of individuals in whom a different management or treatment policy is indicated – for example hypertension is now defined operationally as the level above which therapy is given.
Define Prevalence.
Prevalence – the prevalence of a disease is the number of people in a population with disease at any given time, divided by the total number of people in the population. It is a cross-sectional snapshot of disease in a population.
Describe Incidence.
Incidence – the incidence of a disease is the number of people who develop disease over a period of time.
Outline the different types of study design.
- Cross-sectional studies – a study of a population at a specific point in time, used to measure prevalence, and cross-sectional associations between disease prevalence and ‘exposure’.
- Case-control studies - the characteristics of people with disease (cases) are compared with people without disease (controls). For example: a case control study for lung cancers would compare cases (individuals with lung cancer) with controls (individuals without lung cancer).
- Follow-up (longitudinal or cohort) studies – these involve following up a defined population over a period of time, and can measure incidence and look prospectively at the association between exposure and onset of disease.
- Intervention studies or randomised controlled trials – where some people receive a treatment or preventative measure, and others don’t or get a placebo or different treatment. Clinical trials of new drugs in medicine are an example of this.
Outline a cross-sectional study.
Cross-sectional studies – a study of a population at a specific point in time, used to measure prevalence, and cross-sectional associations between disease prevalence and ‘exposure’.
Outline a case-control study.
Case-control studies - the characteristics of people with disease (cases) are compared with people without disease (controls). For example: a case control study for lung cancers would compare cases (individuals with lung cancer) with controls (individuals without lung cancer).
Outline a cohort study.
Follow-up (longitudinal or cohort) studies – these involve following up a defined population over a period of time, and can measure incidence and look prospectively at the association between exposure and onset of disease.
What is meant by the term ‘target population’?
Group we want to know about.
The population in which the results of the study are intended to apply
What is meant by the term ‘sample population’?
Group we choose to sample from.
The population in which the study is conducted
What is meant by the term ‘participant population’?
Those that actually contribute to the study.
The people who take part in the study are referred to as the participants
