Week 05 Flashcards

1
Q

Meta means…

A

beyond

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2
Q

What does a meta-analysis do….?

A

summarises results, improves precision of estimates of effects in population

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3
Q

Do all systematic reviews have meta-analyses?

A

No

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4
Q

______ review is the traditional literature review where author selects, reads and summarises without systematic process

A

narrative

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5
Q

A narrative review has risk of ___

A

bias (unreliability)

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6
Q

Which is more reliable, narrative or systematic review?

A

systematic

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7
Q

What are some disadvantages of systematic reviews/meta analysis ?

A
  • Cant review information that isn’t there
  • Can’t improve on poor quality information
  • May be difficult to validly combine statistical results from studies with different methods
  • Many systematic reviews give open finding (inconclusive) because sufficient high quality studies are lacking
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8
Q

A ____________ is a statistical method of combining results from multiple studies

A

meta-analysis

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9
Q

“pooled effect size” is a _____ result combining samples from multiple studies

A

single

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10
Q

Do larger or smaller samples provide more precise estimates?

A

Larger (more information)

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11
Q

List reporting biases affecting whether research findings are published at all (4)?

A
  • Publication bias: unfashionable research topics may miss out on publication
  • Time lag bias: rapid or delayed publication of results
  • Duplicate publication bias: the same research findings published in more than one article; also known as “salami slicing”
  • Outcome reporting bias: marked preference for studies with “significant” results; non-significant may be just as important
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12
Q

List biases affecting whether report included in review (4)?

A
  • Citation bias: whether the report appears in a reference list affects its chance of being spotted
  • Database inclusion bias: article not in database is harder to find
  • Language bias:
    preferences for studies in english
  • Personal biases of researchers doing the review
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13
Q

Funnel plot shows effect size by ____ size

A

sample

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14
Q

Bias against trials with small samples and negative/positive effects?

A

negative

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15
Q

If no publication bias, funnel plot will look symmetrical or asymmetrical?

A

symmetrical

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16
Q

Heterogeneity = ??

A

difference or diversity

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17
Q

Can clinical heterogeneity can cause statistical heterogeneity ?

A

Yes

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18
Q

Appraising systematic reviews: Validity of the methods used in the review

A
  • Clearly focussed question with clear eligibility criteria
  • High quality, relevant studies
  • Assessment of bias in the studies
  • Results combined across studies, but only if reasonable to do so
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19
Q

Appraising systematic reviews: Results of the review

A
  • Overall results of the review are presented

- Results are sufficiently precise

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20
Q

Appraising systematic reviews: Relevance of the results to your clinical practice

A
  • Outcome considered from the practitioners perspective

- Applicability of results to your own target population

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21
Q

What is ecological fallacy?

A

“what applies to the group, will also apply to the individual”

  • not sound concept
  • Internal validity threat
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22
Q

Value of systematic reviews to practitioners depend on (2)?

A
  • Availability and quality of primary studies for review

- Methods used to conduct the review

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23
Q

Meta-analysis estimates overall statistical effect size

A
  • Effectively increases the sample size, leading to higher precision
  • Feasibility affected by heterogeneity among studies
  • Can identify bias in individual studies
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24
Q

Standard review process applies to quantitative research

A
  • Strong emphasis on clinical trials but observation studies eligible
  • Qualitative research developing alternatives - meta synthesis
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25
Q

Systematic reviews can/can’t be affected by same biases as primary studies and biases specific to systematic reviews (cannot improve on original evidence quality –> heterogeneity is a risk)

A

can

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26
Q

Accidental, chance differences between same means and population average can lead to the risk of the researchers wrongly believing that sample accurate for whole population —> this is where ___ ____ comes in

A

inferential statistics

27
Q

Rarely possible to get complete data from population (impractical, extensive, instead researchers rely on _____ drawn from the population—> therefore, most quantitative research is at risk of sampling error)

A

samples

28
Q

Descriptive statistics describe the sample….?

A

mean, mode, median, SD, min, max, range amount etc

29
Q

How to sample results generalise beyond the sample affects the ___ validity

A

external

30
Q

Population parameters (statistics) =

A

measurement or results for populations (means, SD, median numbers ratio etc)

31
Q

Inference =

A

conclusion based on information (see smoke –> information, conclude there is a fire –> inference)

32
Q

Inferential statistics enable conclusions (inferences) about _____ when only _____ data is available

A

populations, sample

33
Q

Inferential statistics deal with ______ information

A

uncertain

34
Q

______ is a prediction about what a result will be before the data is analysed or even collected

A

hypothesis

35
Q

Hypotheses are exploratory or descriptive?

A

descriptive

36
Q

Choosing hypotheses after inspecting the data is bad science… is like

A

asking a question after finding the answer

37
Q

Are hypotheses proved and disproved?

A

No, they are either consistent or inconsistent

38
Q

Null hypothesis is _____ the hypothesis

A

against

39
Q

Null hypothesis is called H___

A

H0 (against hypothesis)

40
Q

Alternative hypothesis is ___ the hypothesis

A

for

41
Q

Alternative hypothesis is H___

A

H1 (For hypothesis)

42
Q

Hypotheses are usually state or implied?

A

Implied

43
Q

A _____ hypothesis is something that does not happen, no effect, treatment does not work, effect size = 0 (no difference between groups)

A

null (H0)

44
Q

A _____ hypothesis is something that does happen, is effect, treatment works, effect size is NOT 0 (there IS a difference between groups)

A

alternative

45
Q

Is a non-zero effect the same as “treatment works”… explain why

A

No, because it does not state the direction (could harm or benefit pt, AND doesn’t account for minimal significance)

46
Q

Equivalence is ________ hypothesis

A

nondirectional

47
Q

Equivalence/nondirectional hypothesis are ____ interesting because we want to find benefit but the default statistical significance test

A

rarely

48
Q

Superiority - directional hypothesis, H0 & H1:

A
  • H0: treatment is not superior = does not have a larger beneficial effect than control
  • H1: Treatment is superior = does have a larger beneficial effect than control
49
Q

Equivalence - nondirectional hypothesis, H0 & H1:

A
  • H0: treatment and control have equal effects, no difference
  • H1: Treatment and control have non-equal effects, a difference in either direction
  • H1: goes either way, treatment better OR worse than control
50
Q

Non-inferiority - directional hypothesis, H0 and H1:

A
  • H0: treatment is “not unacceptably worse” than control
  • H1: treatment is unacceptably worse than control
    (common but questionable for EBP)
51
Q

Hypotheses are about ______, not samples

A

populations

52
Q

Hypotheses are for making ______ about populations based on sample data

A

inferences

53
Q

Inference is a conclusion (about the ______) based on information (from the ____)

A

population, sample

54
Q

Method to test inferences is ___ _____ that use sample data to infer beyond sample

A

inferential statistics

55
Q

Inferences from sample to population are _____ –> thats why inferential statistics deals with it

A

uncertain

56
Q

Qualitative research typically ____ hypotheses

A

avoids

57
Q

H0 null hypothesis goes with statistical non-significance p ___ .05

A

> (greater than)

- zero effect

58
Q

H1 alternate hypothesis goes with statistical significance p ___ .05

A

< (less than)

- non zero

59
Q

If p < .05, ____ than 5% chance of sample effect if H0 is true

A

less (unlikely data)

60
Q

If p < .05, ____ than 5% chance of sample effect if H0 is true

A

more (likely data)

61
Q

Type 1 error…?

A

H0 is falsely rejected when p < .05

- accidental error not calculation error

62
Q

Type 2 error…?

A

H0 is falsely retained when p > .05

63
Q

Limitations to hypothesis testing

A
  • Clinicians want to know HOW WELL intervention works, not whether effect is zero
  • H1 “non zero” not informative for EBP (if rejected, all we know is data is unlikely true, what use is that?)