CSH600 Final Exam

What are the 5 steps of evidence

What are the 5 steps of evidence

Ask
Aquire/access
Appraise
Apply
Audit

What framework is involved in the ASK step?

PICO

What does PICO stand for?

P- Patient population of interest
I - Intervention of interest
C - Comparison of interest
O - Outcome

What does the AQUIRE/ACCESS step entail?

Locating evidence

What does the APPRAISE section entail?

Crticially apprasing the evidence using checklist and by asking specific questions

What does the APPLY section entail

Applying this evidence to a patient, whike taking into account the pateints situation and individual needs

What does the AUDIT section entail

Reveiwing the process you have undertaken and commenting on strengths and weaknesses

What is qualitative research?

a systematic, subjective approach to research that is used to describe life experiences and situations and give them meaning.

What is quantitative research?

a formal, objective, systematic process in which numerical data are used to obtain information about the world.

What is a descriptive study?

Focuses on describing a situation or phenomenon without trying to explain why it happens. It provides a detailed picture of what is happening, but it doesn't delve into the reasons or connections between variables.

What is an analytical study

Tries to understand why something happens or how different factors are related. It goes beyond just describing and aims to analyze the relationships between variables.

What is an observational study?

Researchers OBSERVE what is occuring only, without interfering

What is an experimental study?

Reasearchers both control and intervene in the study and observe what happens.

What is a cross-sectional study?

- Analyses and compares two groups at a single snapshot in time
- could be considered buth analytic and descriptive

What is an ecological study

- Compared levels of exposure and/ or disease across populations/ groups (NOT INDIVIDUALS)
- could be considered both analytic and descriptive

What is a cohort study?

- follows a group of people over time who HAVE been exposd to a possibke risk factor, and a group that HAVE NOT been exposed
- the incidence of the outcome in the exposed group is compared to the incidence of the outcome in the group who were not exposed

What is a case-control study?

-Compares a group of people who have the outcome of interest, with a group of people who do not (control)
- then compare their exposure history

Compare cohort and case-control studies

-cohort studies always start with the EXPOSURE status of the patients, then look for te outcome of interest e.g. smoker or non smoker
-case control stduies always start with the OUTCOME status then look for the exposure of interets e.g. cancer or no cancer

What is a randomised controlled trial?

- special type of cohort study
- examines cause and effect relationship between predictor and outcome variables
- at least two groups
- randomisation - ensures groups are similar as possible at start of study

What are inferential statistics?

Allow us to take information from a sample and apply that to a population

What is probability?

likelihood that a particular event will occur

What is a hypothesis

- An unproven theory
- e.g. patients who take drug A will have a better outcome than pateints who take drug B
- in research this is reframed as a null hypothesis

What is a p-value?

- Provides us with information on the PROBABILITY that the differnce we find is due to chance alone
- less than 0.05 = statistically significant

What is the difference between a Type 1 and Type II error?

Type 1 = we reject the null hyothesis when it is actually true
Type II = we accept the null hyothesis when it is actually false

What is a confidence interval?

range of values in which a specified probability of the means of repeated samples would be expected to fall
- e.g. with 95% confidece, the true value is between the lower and upper limits

What is risk?

- Same meaning as probability
- number if times it is likely to occur / total number events possible

What are odds?

- Another way of expressing chance
- number of times an event is likely to occur / number of times it is likely NOT to occur

What is relative risk

It compares the amount of disease / outcome / event in one group relative to that in another

What is Number Needed to Treat

Number of patients who must be treated with the intervention, compared to the control, for ONE to benefit

What is confounding?

A factor outside of the factors being measured that could impact the final result

What is a forest plot?

a graphical display of estimated results from a number of scientific studies addressing the same question, along with the overall results

List the types of trials from strongest to weakest

Randomised conteolled trial, cohort study, case control study, cross sectional study, ecological study, case reports/series

What are continuous outcomes

- Statistics & numbers

What are dichotomous outcomes

- Not numbers, only compares two groups

What is the number needed to harm (NNH)

The number of subjects treated fo rone extra subject to have an adverse outcome, compared with the control intervention

What is clinical significance

Judges whther the differences are worthwhile in real life / in the clinical workplace

What is sensitivity?

Proportion of people WITH the disorder who test POSITIVE

What is specificity?

proportion of people without the disease who test NEGATIVE

What is a positive predictive value

probability that a pt w/ a positive test truly has the disease. The more specific a test, the higher its PPV

What is a negative predictive value

probability that a pt w/ a neg test truly does not have the disease. The more sensitive a test, the higher its NPV.

What are likelihood ratios?

Likelihood ratios are used for assessing the value of a diagnostic test. They use the sensitivity and specificity of the test to determine whether a test result indicates that a condition exists

What is the correct order of the six level pyramid from top to bottom

Studies
Synopses of studies
Synthesis
Synopsis of synthesis
Summaries
Systems

What term can be used to narrow a search strategy?

AND

What would be the simplest way to search for evidence containing variations of the word 'train', such as 'training' or 'trained'?

By using a truncation symbol

If you are searching the Cochrane data base of systematic reviews, you are searching for evidence from which level of the 6S pyramid?

Synthesis

What are the words AND and OR better known as

Boolean operators

What study design is the lowest on the evidence pyramid

Background info/expert opinion

A study in which a group of participants is given an intervention and followed for a period of time without the use of a comparison group is known as?

An uncontrolled study

Which type of randomisation involves randomising whole schools, hospitals, or communities to either the intervention or control group

Cluster randomisation

When searching for evidence about the effectiveness of a particular intervention, what type of studies should you first search for?

Systematic reviews of ranomised controlled trials

The principle that in a randomised controlled trial, all participants should be analysed in the same group as they were randomised to, whether or not they received that particular treatment is known as?

Intention to treat analysis

The absence of a control group means that bias can commonly occur in uncontrolled studies. One such bias occurs because results tend to move towards a mean the more they are measured. This type of bias is known as:

Regression to the mean

What is pull information?

Evidence that you locate yourself and 'pull' from a database etc

What is push information?

Evidence that has been given to you without you looking, and is 'pushed' towards you

A study in which a group of participants is given an intervention and followed for a period of time without the use of a comparison group is known as?

An uncontrolled study

Which type of randomisation involves randomising whole schools, hospitals or communities to either the intervention or control group?

Cluster randomisation

When searching for studies about the effectiveness of a particular intervention, what type of studies should you first search for?

Systematic reveiws of randomised controlled trials

The principle that, in a randomised controlled trial, all participants should be analysed in the same group they were randomised to, whether or not they received that particular treatment, is known as?

Intention to treat analysis

If a study reports a change in the distance a patient could walk after an exercise intervention as it's primary outcome measure, what type of data is being measured?

Continuous

Considering dichotomous data from a randomised controlled trial, how can the size of an intervention effect be presented?

The risk or probability of the event in the intervention group divided by that in the control group

A test with a specificity of 98%, compared to a test with a specificity of 67%, will find?

Fewer false positives

What is verification bias

Verification bias occurs when information is more thoroughly checked or verified for one group than for another, leading to an inaccurate representation of reality.

What is a negative predictive value

The probability that people will not have the disorder when you test negative

What is a positive predictive value

The probability that people will have the disorder when they test positive

What is selection bias

When groups are different from the beginning (the point of choosing people to actually be in the study)
Like picking certain people for the study because they are different from the rest of the population and may influence the results in a way that the investigators want

What is allocation bias

Occurs when there is a difference in how partipants are assigned to different groups in a study. Its like someone is deciding who gets the control and who gets the intervention, meaning its biased.

What is maturation bias?

Refers to the changes or developments that naturally occur over time that may effect the outcomes of a study or experiment

What is confirmation bias

The tendency for people to give more prefernce to information or outcomes that confirm their exisiting beliefs or opinions

What is incorporation bias

If the test that is being evaluated is included in the reference standard

Leads to overestimation of test accuracy

What is the Hawthorne effect?

the alteration of behavior by the subjects of a study due to their awareness of being observed.

What is a prognosis?

prognosis refers to the likely course or outcome of a medical condition. It involves predicting how a person's health is expected to develop, including the chances of recovery or deterioration. Prognosis is often based on factors such as the nature and severity of the illness, available treatments, and individual characteristics of the patient.

What is a diagnosis?

a diagnosis is the identification or recognition of a medical condition or disease. It involves determining the nature and cause of an illness or health problem based on symptoms, medical history, and often, diagnostic tests. The goal of a diagnosis is to understand what is causing a person's symptoms or health issues so that appropriate treatment and management can be provided

What is intervention?

In simple terms, an intervention is a purposeful action or step taken to improve a situation, solve a problem, or prevent a negative outcome

What are the 5 hierarchies of evidence for intervention from top to bottom?

A systematic review
RCT
Pseudo-randomised controlled trials
Cohort study/case control study
Case series

What are the 5 hierarchies of evidence for diagnosis from top to bottom

-Systematic reviews
-A study of test accuracy with an independent, blinded comparison with a valid reference standard, among consecutive persons with a defined clinical presentation
-Same as level II but uses non-consecutive participants
-A comparison with a reference standard that does not meet the criteria required for higher than level II evidence
-Study of diagnostic yield

What are the 5 hierarchies for prognosis from top to bottom

-Systematic reviews
-Prospective cohort study
-Analysis of the prognostic factors among the participants in one group of a randomised controlled trial -retrospective cohort study
-Case series or cohort study