CAT (PP) lecture Flashcards
Inverse Care Law
- The availability of good medical care tends to vary inversely with the need for it in the population served
- The inverse care law operates more completely where medical care is most exposed to market forces, and less so where such exposure is reduced
What are the components of a person’s socio-economic status?/ individual level measurements
- education level
- occupational class
- income level
- N-SEC (new socioeconomic classification based on occupation)
What do area-based measures measure?
Level of material and social disadvantage of the area in which a person lives
Examples of ‘area-based’ measurements
- English Index of Multiple Deprivation (IMD) (linked to post-code)
- Scottish Index of Multiple Deprivation (SIMD)
- Carstairs Index (Scotland)
- Townsend Index of material deprivation
What’s interpretive paradigm?
- The interpretive paradigm is concerned with understanding the world as it is from subjective experiences of individuals
- They use meaning (versus measurement) oriented methodologies, such as interviewing or participant observation, that rely on a subjective relationship between the researcher and subjects
What is interpretivism in research?
- Interpretivism is one form of qualitative methodology
- Interpretivism relies upon both the trained researcher and the human subject as the instruments to measure some phenomena, and typically involves both observation and interviews
What are the criteria to evaluate the quality of a service provision?
Maxwell criteria (3As and 3Es)
- accessibility - can people even access it eg appointment etc
- appropriate - is it relevant
- acceptability - and what people want, is it viewed positively
- equity - is it fair
- efficiency - is it efficient - cost effective
- effectiveness - does it even work
What is ecological fallacy?
When inferences about the nature of individuals are deduced from inferences about the group to which those individuals belong
What’s type 1 error?
A rejection of a true null hypothesis
(so we think that our findings are brilliant, but it turns up that the nill hypothesis is true)
What’s type 2 error?
type II error is the failure to reject a false null hypothesis
(so we think that our findings are shit - pessimist, but in fact it’s good as we are opposite to null hypothesis)
What’s the aim of Bradford-Hill criteria?
outlines 9 minimal conditions needed to establish a true causal relationship
Describe the meaning of each of Bradford-Hill criteria (9)
- TEMPORALITY does the cause come before the effect?
- REVERSIBILITY if the cause is removed does the effect go away?
- DOSE-RESPONSE RELATIONSHIP/BIOLOGICAL GRADIENT
If exposure to the cause goes up does the effect?
- STRENGTH
How strong is the association between the cause and effect (relative risk)?
- PLAUSIBILITY
Does the association conform with current knowledge?
- CONSISTENCY
If the study was replicated in a different time and place
would the same association be observed?
- STUDY DESIGN
Does the evidence come from a strong, robust study?
- SPECIFICITY
Considered to be the weakest of the criteria; a single
cause produces a specific effect
- ANALOGY
Applying accepted evidence from another area of study
What’s The Short Form (36) Health Survey?
- is a 36-item, patient-reported survey of patient health
- SF-36 is a measure of health status
- an abbreviated variant of it, the SF-6D, is commonly used in health economics as a variable in the quality-adjusted life yearcalculations -> to determine the cost-effectiveness of a health treatment
What’s the Bayesian approach?
It’s a statistical method that updates the probability for a hypothesis as more evidence or information becomes available
‘How likely is that disease now I know this abnormal test given that disease is present?’
What’s the frequentist approach?
‘how likely is an abnormal test given that disease is present?’
Frequentist inference is a type of statistical inference that draws conclusions from sample data by emphasizing the frequency or proportion of the data
What’s CONSORT?
Consolidated Standards Of Reporting Trials
Various initiatives developed by the CONSORT Group to alleviate the problems arising from inadequate reporting of randomized controlled trials
What’s consort statement?
- CONSORT statement - it’s the main product of CONSORT group
(group that aims to address the problems that arise from inadequate RCT reporting)
- minimum set of recommendations for reporting randomized trials
- a standard way for authors to prepare reports of trial findings-> reducing the influence of bias on their results, and aiding their critical appraisal and interpretation
- it’s 25-item checklist
What does GRADE mean? Full name
GRADE (Grading of Recommendations, Assessment, Development and Evaluations)
What’s GRADE?
- a transparent framework for developing and presenting summaries of evidence
- a systematic approach for making clinical practice recommendations
- the most widely adopted tool for grading the quality of evidence and for making recommendations
What’s incidence?
Incidence – Number of new cases
What’s the prevalence?
Prevalence – Number of existing cases
Point vs period prevalence
POINT PREVALENCE:
“a snapshot in time” showing the amount of people in that one investigation who have the illness (e.g. cross-sectional studies)
PERIOD PREVALENCE:
Refers to a specific PERIOD (usually a year)
What’s case fatality rate?
Number of deaths from a disease/Number of diagnosed cases of the disease
*produces a percentage of people that die from a specific disease
* denominator - new cases
What are the confounders associated with?
With exposure and outcome
What are QUALYs ?
QALY:
- Capture expected years of life left and the quality of that time
- Derived from mortality, morbidity and a quality of life value
What’s case-mix?
Case-mix
- adjustment is an attempt to control for a particular type of confounding, namely that some patients have a set of covariate risk factors that predispose them to the outcome
- comparison of treatment outcomes between providers with differing mix of patients with regard to diagnoses, severity of illness, and other variables associated with the probability of improvement with treatment
What’s information bias?
Information bias
- results from systematic differences in the way data on exposure or outcome are obtained from the various study groups
- individuals may be assigned to the wrong outcome category -> leading to an incorrect estimate of the association between exposure and outcome
What’s observer bias?
Observer bias
- may be a result of the investigator’s prior knowledge of the hypothesis under investigation or knowledge of an individual’s exposure or disease status
- Such information may influence the way information is collected, measured or interpretation by the investigator for each of the study groups
What’s recall bias?
- patient’s ability to accurately recall past exposures
- recall bias may occur when the information provided on exposure differs between the cases and controls
What’s social desirability bias?
Social desirability bias
- respondents to surveys tend to answer in a manner they feel will be seen as favourable by others, for example by over-reporting positive behaviours or under-reporting undesirable ones
What’s performance bias?
Performance bias
- study personnel or participants modify their behaviour / responses where they are aware of group allocations
What’s detection bias?
Detection bias occurs where the way in which outcome information is collected differs between groups
What’s instrument bias?
Instrument bias refers to where an inadequately calibrated measuring instrument systematically over/underestimates measurement.
What’s selection bias?
Selection bias occurs when there is a systematic difference between either:
- Those who participate in the study and those who do not (affecting generalisability) or
- Those in the treatment arm of a study and those in the control group (affecting comparability between groups).
What’s sampling bias?
Sampling bias - the scenario in which some individuals within a target population are more likely to be selected for inclusion than others
For example, if participants are asked to volunteer for a study, it is likely that those who volunteer will not be representative of the general population, threatening the generalisability of the study results. Volunteers tend to be more health conscious than the general population.
What’s allocation bias?
Allocation bias occurs in controlled trials when there is a systematic difference between participants in study groups (other than the intervention being studied). This can be avoided by randomisation.
What type of data collection is used in cohort study?
Longitudinal
What in randomisation (in adjustment for confounding)?
- all potential confounding variables should be equally distributed between the study groups
- it involves the random allocation (e.g. using a table of random numbers) of individuals to study groups
What in restriction (in adjustment for confounding)?
- Restriction limits participation in the study to individuals who are similar in relation to the confounder
For example, if participation in a study is restricted to non-smokers only, any potential confounding effect of smoking will be eliminated.
What in matching (in adjustment for confounding)?
- Matching involves selecting controls so that the distribution of potential confounders (e.g. age or smoking status) is as similar as possible to that amongst the cases
- Usually in case-control studies
- Pair matching - selecting for each case one or more controls with similar characteristics (e.g. same age and smoking habits)
- Frequency matching - ensuring that as a group the cases have similar characteristics to the controls
What’s stratification? (in relation to confounders)
Stratification allows the association between exposure and outcome to be examined within different strata of the confounding variable, for example by age or sex
What’s standardization? (in relation for confounders)
Standardisation accounts for confounders (generally age and sex) by using a standard reference population to negate the effect of differences in the distribution of confounding factors between study populations.
What’s residual confounding?
Residual confounding
- It is only possible to control for confounders at the analysis stage if data on confounders were accurately collected
- Residual confounding occurs when all confounders have not been adequately adjusted for, either because they have been inaccurately measured, or because they have not been measured (for example, unknown confounders)
