Study Design Sampling And Recruitment Flashcards
Definition of sample
A small part of something that is intended to represent the whole thing
Definition of population
All persons that have similar characteristics = census
Definition of sampling
The process of selecting a sample from the population to be studied
Definition of external validity
Consider how representative the study participants are of the disease, disability, people, phenomenon in the population
Definition of internal validity
How to chose study participants in order to ensure that the study ca n answer the research aquestionquestion
What are the different probability sampling methods ?
- simple random sampling
- stratified random sampling
- systematic random sampling
- clustered random sampling
What is probability sampling ?
All persons in the target population have equal chance of being selected
Define simple random sampling
The whole population is available for selection
What is stratified random sampling
The whole population is available for selection but sample is selected from sub-groups
What is systematic random sampling
Selection at defined intervals
What is clustered random sampling
For very large population which requires subdivisions into geographical areas
Define non-probability sampling
Selection process does not guarantee equal chances of selection for all entities in the target population
What is convenience sampling ?
Used in qualitative research and case series research, selection is based on availability
What is purposive sampling ?
Must be used in qualitative research, selection is based on the subjective judgment of the researcher that a potential participant can be an expert. May be combined with random sampling for large populations.
What is Snowball sampling ?
When the population is uneasy to access, researcher requests access to colleagues, friends, relatives of a known research participant. It can be used in any type of research (qualitative, quantitative)
What is the goal of PIO question
Report an observation or to associate the effects of intervention with the outcome
What is the goal of PICO question ?
To establish a causal relationship between the intervention and the outcome
What is the goal of qualitative question ?
Observe and describe phenomena. It is also used to describe how people cope with this phenomena.
What are the components of qualitative question ?
- a population
- a phenomenon of interest
- the connection between population and phenomenon of interest
What is delimitation ?
To narrow the focus of your enquiry to a manageable number of items or factors. It means that you identify the potential weakness in the study but also define exclusion and inclusion criteria, determine the research instruments and procedures.
What study design is linked to the word “EFFECTIVE”
RCT
What is prevalence ?
It’s the proportion of the population that has a condition at a specified point in time
What is incidence ?
It’s the number of new cases of a condition during a specific period of time
What study design is linked to words “HOW MUCH EACH (YEAR)”
Cross sectional study
Which sampling method can you use for a cross sectional study were disease register doesn’t exist ?
Clustered random sampling
What type of study design is linked to the word “COPE”
Qualitative study with purposive sampling
Definition of recruitment
The process of getting the right people to agree to participate in your study
What are the recruitment methods ?
- Cold call
- Advertisements
- Direct recruitment
- Snowball sampling
Define cold call
How to : Letter email phone call to people who have never heard about the study
Resources and requirements : public/private records to identify potential participants
Define Advertisement
How to : place adverts in newspapers, internet, television, magazines. Print out posters and flyers and pin them in public places.
Resources and requirements : the target population must regularly access the medium of advertisement
Define direct recruitment
How to : invite patients directly from clinics and hospitals
Resources and requirements : the researcher collaborates with healthcare professionals. The healthcare professionals recruit research participants on behalf of the researcher (the healthcare professional may also be the researcher).
How to snow ball sampling ?
How to : ask current participants to refer their friends and relatives to you
How to get valid consent from people who do not have the capacity to consent
Does this potential participant have an advance notice. If not, the caregiver may get consent from the primary carer.
What is advanced directive ?
Is a legal document prepared by a person to specify how they wish to engage with healthcare services and society at large if they ever loose their capacity to consent
What are the actions of the researcher to ensure ethical principles ?
1) give information to the potential participant
- terms of participation
- how the research will benefit the participant and society
- what are the compensation/ incentives
- right to confidentiality and privacy
- right to withdraw consent at any time
2) Check the capacity to consent
- the ability of the potential participant to use the above mentioned informations provided to make informed decision
3) Give time between information and consent
4) signing the informed consent
Does the cold call violate the ethical principles ?
They don’t if they are used in non invasive types of investigation, ex: qualitative surveys
