How should major changes to protocol NOT be handled?

Continue the study but increase the sample size

A randomly selected, clearly defined sub-pop'n & usually located in 1 place

How frequently should data be backed up?

At an interval that minimises the work required to re-enter the data

What is meant by the power of a study?

The probability that the study will NOT produce a false negative result

The target population:

Should be the same as the study population

Which of the following is a weakness of prospective studies?

They are not useful to study rare conditions

Sign frequency/ point prevalence frequency is:

Proportion of animals w dx which have sign at presentation

An important feature of a randomised control trial is:

There are at least 2 groups , 1 tx group and 1 control group

Which of the following is NOT a technique to identify potential data entry errors?

Formal training & certification of data entry staff

Which of the following is NOT a technique that can be used to help validate the data from a questionnaire?

Asking respondents to sign the questionnaire

Proportionate sampling means:

Random subject selection from each stratum relative to proportion of pop'n

What is the defintion of 95% confidence interval?

That there is a 95% probability that mean answer is correct

What does β represent?

The probability of obtaining a false negative result

Applicability (generalisability) is:

The extent the results of a study are relevant to a given population

Which of the following may NOT have an adverse effect on the quality of the data collected in a study?

Good study documentation & operations manuals

What is a data dictionary?

A formal description of each variable name, format, permissible values etc

Sample size calculations are important because:

They indicate minimum no. of participants to achieve a specified power

Taking into account conditional dependency means that: (choose one)

Frequency of occurance of combo of clincial signs is accurate

Simple random sampling means:

Each subject in target popul'n has equal & independent chance of selection

Which of the following is a weakness of retrospective studies?

The type and quality of measurements cannot be predetermined

Double blinding ensures:

Investigator and owner do not know tx participant is receiving, Investigator does not know tx a participant is receiving

Randomisation of participants in a trial ensures that:

Patients allocated to each intervention w'out selection bias

Which of the following methods is most suitable for randomising animals to intervention groups?

Throwing a dice to determine group allocation

What is the disadvantage of collecting both 'age' and 'date of birth' of subjects?

Effectively same datum, introduces potential for conflicting values

Which of the following is a disadvantage of RCTs?

Sometimes unethical to have untreated control group

When a P value is reported as <0.05 what does this mean?

That there is 5% chance or less of obtaining false positive

Inclusion criteria are:

Requirements that a subject must fulfil to enter a study

The most useful question regarding a test is: (choose one)

What is the sensitivity & specificity?

In cross-sectional studies:

The variables are all measured at a single point in time

How should minor changes to the study protocols be handles?

When changes are made, make a careful record of why & what change was made

What is the value of a power calculation performed after a study has been performed?

A power calc. provides evidence that a -ve result likely to be false -ve

Retrospective studies:

Are conducted backwards in time

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VMS3008 - Vet research & EBVM

94 termsStudBud Administration217 plays

Lecture MCQs

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Questions 94

Answers

1
How should major changes to protocol NOT be handled?
Analyse data using different protcols separately
Continue the study but increase the sample size
Treat data collected before the protcol change as a pilot study
Restart study using revised protocol
2
In which section of a scientific paper are you likely to find analysis of results?
Results
Abstract/ summary
Discussion
Introduction
3
In which section of a scientific paper are you likely to find the scientific question?
Abstract/ summary
Materials and methods
Discussion
Introduction
4
Clusters:
Subjects that are interdependent
A randomly selected, clearly defined sub-pop'n & usually located in 1 place
Subjects that share a characteristic
Same as strata
5
How frequently should data be backed up?
At an interval that minimises the work required to re-enter the data
Monthly
Weekly
Daily
6
What is meant by the power of a study?
The probability that the study will produce a false negative result
The probability that the study will NOT produce a false negative result
The probability that the test will NOT produce a false positive result
The likelihood that the correct no. of samples has been included in a study
7
The target population:
Is the sample to be taken
Is the population not sampled
Should be the same as the study population
Is a sample of the study population
8
Which of the following is a weakness of prospective studies?
They are not useful to study rare conditions
Measuring the exposure to the putative factor is difficult
Measurement of variables relies on historical records or memory
They cannot be used to estimate the incidence of a specified disease
9
Multiple cohort studies are useful for:
Rare risk factors
Studies where time is limited
Common diseases
Multiple risk factors
10
What is the best format to store a variable recording body temperature measured in degrees centigrade?
Logical variable
Text variable
Integer variable
Floating point variable
11
Sign frequency/ point prevalence frequency is:
Sign frequency expected when animal severely ill
Frequency w which signs reported in literature for that dx
Proportion of animals w dx that have sign during dx progression
Proportion of animals w dx which have sign at presentation
12
An important feature of a randomised control trial is:
Subjects are readily available
There are at least 2 groups , 1 tx group and 1 control group
They can be published
They are easy to perform
13
Which of the following is NOT a technique to identify potential data entry errors?
Double entry of data
Manual checking of a proportion of data
Formal training & certification of data entry staff
Examine the distribution of values w'in a data field
14
Which of the following is NOT a technique that can be used to help validate the data from a questionnaire?
Simultaneous collection of data through another instrument
Asking respondents to sign the questionnaire
Comparing data from that collected in other studies or population
Re-testing a subsample
15
How many backup copies should be kept?
3
2
5
1
16
Proportionate sampling means:
Randomly selecting equal numbers from each strata
Selecting proportion of study population
Selecting every n th subject from the population
Random subject selection from each stratum relative to proportion of pop'n
17
When should development & testing of the data management system be performed?
Before the study begins
When writing the paper reporting the results
After data has been collected
During the statistical analysis
18
What is the defintion of 95% confidence interval?
95% probability that trial repeat would produce answer within CI
That there is a 5% probability that result is false positive
That there is 95% probability of a false negative result
That there is a 95% probability that mean answer is correct
19
What does β represent?
The probability of the result being wrong
The probability of obtaining a false negative result
The probability of a type II error
The probability of making a type I error
20
Applicability (generalisability) is:
The cost-benefit of the study
The extent the results of a study are relevant to a given population
The application of the results to all species
The usefulness of the results in general terms
21
Which of the following tx factors are important to consider when designing a clinical trial? (choose one)
Effectiveness & safety of drug
Sample population & generalisability of study
Whether different dose rates will be studies
All of the above
22
Prospective studies:
Usually use records
Collect non-specific data
Do not monitor outcomes
Are conducted forwards in time
23
Which of the following may NOT have an adverse effect on the quality of the data collected in a study?
Poor training of staff
Missing/ fraudulent data
Good study documentation & operations manuals
Relying on hand-written notes
24
Cohort studies are: (choose one)
Useful to study a putative risk factor & the development of a specified dx
Useful for all these reasons
Observational studies
Useful to compare one or more preventative tx
25
What is a data dictionary?
The data management rules
A dictionary of technical terms used by the trial
A formal description of each variable name, format, permissible values etc
An internal file in a relational database
26
Which of the following type of question is an open question?
Numerical entry
Ranking question
Checklist
Multiple choice
27
Sample size calculations are important because:
They indicate no. required to achieve a representative sample of target pop
They indicate minimum no. of participants to achieve a specified power
They indicate maximum samples that can recruited for the study budget
They indicate minimum no. of participants required to give generalisability
28
Taking into account conditional dependency means that: (choose one)
Signs considered to occur independently of one another
Frequency of occurance of combo of clincial signs is accurate
Sign freq'cies cannot be multiplied together to calc. combo of sign freq'cy
None of the above
29
Ideally CDDSS should be compared to: (choose one)
Undergraduates
All of the above
Newly qualified vets
Experts
30
Simple random sampling means:
Each subject in target population has an independdent chance of selection
Each subject in target population has an equal chance of selection
Each subject in target popul'n has equal & independent chance of selection
Each subject in the study population is selected
31
Which of the following is a weakness of retrospective studies?
The type and quality of measurements cannot be predetermined
Lost to follow-up subjects is a problem
The cost of the study is difficult to determine
They are more expensive than prospective studies
32
The best measure(s) of how good or bad a CDDSS is/are:
Accuracy
Specificity & sensitivity
Likelihood ratio of positive test & negative test
Level of agreement w experts
33
Double blinding ensures:
Investigator and owner do not know tx participant is receiving
Investigator does not know tx a participant is receiving
Owner does not know tx a participant is receiving
34
Randomisation of participants in a trial ensures that:
Patients allocated to each intervention w'out selection bias
Investigators are randomly allocated to tx groups
Investigator does not know allocation of subjects to tx
Confounding variables are unevenly distributed tx groups
35
Which of the following methods is most suitable for randomising animals to intervention groups?
Taking animal's name & allocating them to groups in alphabetical order
Throwing a dice to determine group allocation
Putting alternate animals in 2 different groups
Asking owner which group they would like animal to be in
36
What is the disadvantage of collecting both 'age' and 'date of birth' of subjects?
Age can be calculated from date of birth and vice versa
Effectively same datum, introduces potential for conflicting values
Age may be recorded in days/ months/ years so inconsisent recording
Collecting both pieces of info creates redundancy
37
Which of the following is a disadvantage of RCTs?
Cause precedes effect
It is the most powerful study design for data collection
Allocation of subject & no. of subjects to tx is planned
Sometimes unethical to have untreated control group
38
Decision trees are composed of: (choose one)
Chance nodes
All of the above
Terminal nodes
Decision nodes
39
When a P value is reported as <0.05 what does this mean?
That there is 5% chance or less of obtaining false negative
That there is 5% chance or less of obtaining false positive
That there is a 95% chance or more of obtaining false negative
That there is a 95% chance or more of obtaining false positive
40
Inclusion criteria are:
The inverse of the exclusion criteria
Requirements that a subject must fulfil to enter a study
Subjects who want to join the study
The same as the recruitment process
41
Which of the following types of software can be used to process study data?
Database package
Specialist statistical software
Spreadsheet program
Presentation software
42
The most useful question regarding a test is: (choose one)
What is the accuracy?
What is the sensitivity?
What is the sensitivity & specificity?
What is the specificity?
43
In which section of a scientific paper are you likely to find experimental details?
Materials and methods
Abstract/ summary
Results
Discussion
44
In cross-sectional studies:
The variables are measured going forwards in time
The variables are measured going backwards in time
The variables are all measured at a single point in time
No variables can be measured
45
How should minor changes to the study protocols be handles?
Allow changes to be made but make sure operations manuals are updated
Only allow supervisors to make changes when necessary
Give staff discretion to make changes they feel are necessary
When changes are made, make a careful record of why & what change was made
46
What is the value of a power calculation performed after a study has been performed?
There is no value in a post-hoc power calc.
A study result is not statistically significant without a power calculation
A power calc. provides evidence that a -ve result likely to be false -ve
A positive result is not statistcally significant without a power calc.
47
Differences between the sample statistic and the target population parameter value are due to: (choose one)
All of the above
Sample size
Individual variation in the parameter
Probabilities of selection
48
What a type I error?
A false negative result
A false positive result
49
Which of the following categories are most useful to identify information needs? (choose one)
Diagnostic process
Control and prevention
All of the above
Epidemiological risk factors
50
The design providing the strongest evidence about causation is:
Cross-sectional studies
Meta-analyses
Cohort studies
Case-control studies
51
Retrospective studies:
Only include animals that have developed disease of interest
Do not usually use records
Are conducted backwards in time
Only include animals that have been exposed to the putative risk factor
52
When evaluating a CDDSS the test data should consist of:
Cases from a range of dx represented in the database
Cases from a range of dx found in target population
Practioner derived cases
Expert derived cases
53
The most appropriate design to study potential risk factors in rare diseases is:
Meta-analyses
Case-control studies
Randomised controlled trials
Cohort studies
54
Which of the following is an advantage of cross-over designs?
Because subjects act as their own control, sample size can usually be red.
Tx w persistent actions confound results
Statistical appraisal simple
It has greater validity than parallel RCTs
55
What course of action should be taken when an error in a data file is detected?
Correct data, record correction in data log & proceed to analysis
Correct data and proceed to analysis
Analyse data omitting erroneous data
Discard data file & re-enter data from scratch
56
Which of the following are NOT useful in arriving at a final design for a questionnaire?
Showing the draft design to colleagues
Pilot testing the questionnaire
Repeating questions w different wordings
Fixing clear survey objectives
57
Severity analysis in modelling is: (choose one)
All of the above
A measure of how good the model is
Evaluating the impact of changing the value of a variable
The number of times the model was correct
58
Decision tree decision nodes are nodes where:
A conscious decision between two or more options is made
Utilities are attached to nodes
No decision are made, likelihoods are attached to each outcome
59
In which section of a scientific paper are you likely to find new knowledge?
Materials and methods
Abstract/ summary
Results
Discussion
60
Which of the follwoing is the best method of blinding the lab analysis of samples?
Ask lab to blind samples
Leave all data labelled but use independent lab
Send samples from different groups to different labs
Pre-label sample pots using numeric code giving no indication of animal ID
61
In which section of a scientific paper are you likely to find hypothesis?
Discussion
Materials and methods
Abstract/ summary
Introduction
62
In case-control studies:
The variables are measured going forwards in time
The variables are measured going backwards in time
The variables are measured at a signle point in time
Outcomes are not used
63
Which of the following are NOT positive factors in maximising the response to a questionnaire?
Short questionnaire
Advance warning of survey
Choice to opt out
Personalised form
64
When calculationg treatment and testing thresholds, possible outcomes may be: (choose one)
All of the above
Probability of disease in patient is testing band
Probability of disease in patient is below testing threshold
Probability of disease in patient is above treatment threshold
65
Which of the following provides evidence of quality control?
Automatic biochemical analyser serviced on time
Radiographs are developed using an automatic developer
Clinical pathology lab is part of independent audit scheme
66
CDDSS are most useful when used by:
Experts
Non-experts
67
Sampling is used because:
It gives reliable results
It provides an estimate whilst reducing the time and cost
It is quick and easy to do
It requires no planning
68
Algorithms w decision nodes are best suited to:
Signs frequencies of 1-99%
Simple categorical info for which answers to all the nodes are available
Categorical clinical info
69
In which section of a scientific paper are you likely to find the formulation of the problem?
Abstract/ summary
Materials and methods
Discussion
Introduction
70
Incidence can be measured using:
Cohort studies
Meta-analysis
Cross-sectional studies
Case-control studies
71
Which of the following is a strength of prospective studies? (choose one)
They are useful to study rare conditions
Important variables can be accurately measured w'out reliance on records
All of the above
They are useful to study conditions w a long incubation period
72
What is meant by a two-tailed hypothesis?
Tests two hypotheses
Diff. may be due to dec. in measured vlaue
Accepts that diff. may be due to either an inc. or dec. in measured value
Hypothesis that suggests there is no diff. between two groups
73
What is a negative factor in maximising the response to a questionnaire?
Monetary incentive
Relevance of questionnaire to participent
Sensitive question included
Reminders
74
Decision tree chance nodes are nodes where:
A conscious decision between two or more options is made
No decision are made, likelihoods are attached to each outcome
Utilities are attached to nodes
75
Assuming conditional independence of clincial signs means: (choose one)
Frequency of occurance of combo of clincial signs is accurate
Sign freq'cies cannot be multiplied together to calc. combo of sign freq'cy
None of the above
Signs considered to occur independently of one another
76
Which of the following should not be included in a covering letter?
Why you have selected the addressee/ respondent
Personal details of other people being surveyed
Purpose of the survey
Instructions on how to return the questionnaire
77
In which section of a scientific paper are you likely to find the project plan?
Abstract/ summary
Discussion
Materials and methods
Results
78
Matching in case-control studies:
Reduces sampling bias
Reduces the cost of the study
Reduces the size of the control group
Reduces the number of variable measurements that need to be made
79
Which of the following would NOT increase compliance?
Motivational meetings
A long study period & complex tx regime
Detailed tx instructions
Financial inducements
80
Owner utilities can be obtained by using: (choose one)
Dialogue
Visual analogue scales
Standard gamble techniques
All of the above
81
How long should raw data from a study be kept for?
Until study report has been written
Until data has been analysed
1 year after publication of report
For several years/ as long as practicable after report publication
82
What tests should be used to compare the means of 2 sets of measurements when samples are paired?
Chi-squared test
One-way analysis of variance
Student's t test
Mann-Whintney U test
83
What is a type II error?
A false negative result
A false positive result
84
What is a Likert scale?
A Q asking how strongly a person agrees or disagrees w a statement
A type of open question
A Q where person is asked from 1-10 how much they agree w a statement
A measure of how good a question is
85
In which section of a scientific paper are you likely to find new scientific questions?
Results
Discussion
Abstract or summary
Introduction
86
Which of the following is a strength of retrospective studies?
They are more expensive than prospective studies
They are useful to study rare conditions
Measurement of variables rely on historical records or memory
Recall bias is not a problem
87
What is the relationship between sample size calculation for one-tailed and two-tailed hypotheses?
Size for 1-tailed at particular α level is same as for 2-tailed at half α
Size for 1-tailed is twice that for 2-tailed
Size for 1-tailed at particular α level is same as for 2-tailed at 2α
Size for 1-tailed is 1/2 that for 2-tailed
88
Ideally a CDDSS would take into account: (choose one)
Signs not observed
Signs observed
Signs not examined
All of the above
89
Stored samples from subjects in a nested case-control study
Provide a reference base line
Enable selective testing of the cohort once outcomes are known
Remove the need for further measurements
Reduce confounding
90
Decision tree terminal nodes are nodes where:
A conscious decision between 2 or more options is made
Utilities are attached to these nodes
No decision are made, likelihoods are attached to each outcome
91
What is a correlation coefficient a measure of?
The strenght of linear association
The variability of a measure
The intervals between data
Statistical power
92
In which section of a scientific paper are you likely to find what is known and not known?
Materials and methods
Discussion
Abstract/ summary
Introduction
93
In which section of a scientific paper are you likely to find interpretations and conclusions?
Discussion
Abstract/ summary
Materials and methods
Results
94
Important criteria for exclusion would be: (choose one)
Knowledge that being in placebo group would adversely effect patient
Subjects unlikely to comply w tx/ recording of measurement
Knwoledge that tx unsafe in a defined subset of target population
All of the above

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