Week 2- Research Design Overview Flashcards
Levels of evidence- systematic reviews
Secondary study
Level 1 bias
Description: combines all lower level primary studies to get a conclusion
Strengths: summary of evidence. Good validity. Greatly reduced bias.
Weaknesses: time consuming. Only as strong as the weakest study. Means it can be prone to biases. Relies on data being available.
Levels of evidence- RCT (randomised control trial)
Primary study: experimental
Level 2 bias
‘Randomised’ refers to how we allocate people to each group. Two types, parallel trials and crossover trials.
Strengths: strongest primary design. Used to determine the effectiveness of an intervention. Good reliability and validity.
Weaknesses: time consuming. Expensive. Only looks at one or two variables. Lots of resources required.
Levels of evidence- Quasi (pseudo trial)
Primary: experimental study
Level 3.1 bias
Description: almost identical to RCT but isn’t randomised. Eg. testing genders or races against each other.
Strengths: easy to set up. Realistic (can take place outside a lab). Useful when it’s unethical to manipulate the IV.
Weaknesses: subject to allocation bias. Could be difficult to determine causation.
Levels of evidence- cohort
Primary: observational study
Level 3.2 bias
Description: two types, prospective and retrospective. Prospective looks at a group of people exposed to something and follows them over a period of time.
Strengths: suitable for rare exposures. Can assess exposure on multiple outcomes. Less prone to recall bias.
Weaknesses: not suitable for rare outcomes if the subject doesn’t develop the desired outcome, time is wasted. High dropout rates
Levels of evidence- case control
Primary: observational study
Level 3.3 bias
Description: always retrospective= looking back to see if there’s a relationship with an exposure.
Strengths: suitable for rare outcomes. More cost effective because less resource and time intensive. Useful for looking at multiple exposures.
Weaknesses: very prone to recall bias. Can not determine causation.
Levels of evidence- cross sectional (prevalence study)
Primary: observational study
Level 4 bias
Description: “snapshot”. Descriptive study of a group of people at one point in time. Eg. census
Strengths: cost effective. Quick and easy.
Weaknesses: relies on self report. Only valid at one point of time.
Levels of evidence- correlational
Primary: observational study
Level 4 bias
Description: used to assess the relationship between two variables. Testing a relationship.
Strengths: useful to determine an indicative relationship. Stimulates further study.
Weaknesses: correlation does not equal causation
Levels of evidence- case series
Primary: observational study
Level 4 bias
Description: group of cases presenting similarly in disease or symptoms. No control groups. Hypothesis generating. Eg. HIV first discovered
Strengths: lots of in depth info on a small group. Realistic. Useful for measuring naturally occurring things.
Weaknesses: small sample which limits validity. Can’t generalise. Mixture of self reports and observations
Levels of evidence- case study
Primary: qualitative study
Level 5 bias
Description: in depth study on either a person or disease
Strengths: hypothesis generating. Rich and in depth info on topic. High internal validity
Weaknesses: limits reliability. No generalisation
Levels of evidence- grounded theory
Primary: qualitative study
Level 5 bias
Description: creating a theory from data gathered from a group of people. The theory is “grounded in actual data”
Levels of evidence- phenomenology
Primary: qualitative study
Level 5 bias
Description: aims to understand the lived experience of a person in relation to a concept. Focuses on that persons experience in a certain situation
Levels of evidence- ethnography
Primary: qualitative study
Level 5 bias
Description: researchers observe or interact with a study’s participants in their real life environment. Creates shared understanding.
When to use PICO/ PEO
When identifying the question you want to address, depending on weather you’re looking at qualitative or quantitative research
Purpose of PICO/ PEO
Provides a framework for formulating patient-specific clinical questions.
PICO stands for and study type used for
Quantitative studies
P- patient problem (or population). What are the characteristics of the population or patient
I- intervention. How do we wish to intervene
C- control/ comparison. Alternative intervention
O- outcomes. What are the possible outcomes
Eg. (P) in middle aged male amputees suffering from phantom limb pain, (I) is gabapentin, (C) compared with placebo, (O) effective in decreasing pain.
PEO stands for and study used for
Qualitative
P- population
E- exposure
O- outcome
PICo stands for and study used for
Qualitative
P- population or problem. Characteristics of the population or patient.
I- interest. Relates to defined event, activity, experience or process
Co- context. The setting or distinct characteristics.
Eg. (P) what are caregivers, providing home based care to patients with Alzheimer’s disease, (I) experiences in (Co) Australia.
