# Threats to Internal Validity Flashcards

1
Q

What is chance?

A

Where we have the pressence of random error which is inherent in all measurement.

More error is not good

2
Q

How do we measure chance?

A

Using the p-value

3
Q

What is a P value?

A

Probability representing the strength of evidence to support hte null hypothesis

4
Q

What is a Large P value of >0.05 represent?

A

Supports the Null hypothesis hence their is no statistically significant difference between to two groups

5
Q

What is a samll p value of <0.05 represent?

A

We reject the null hypothesis hence there is a statistical significance between the two groups’ results

6
Q

What is the overall theme of what is the p value really saying?

A

The probability the results are due to chance rather than a real treatment effect

7
Q

How do we deal with chance?

A

Increase sample size
Recognize the extent via statistics and interpret the results accordingly

8
Q

What is important with respect to chance and statistical significance?

A

Does not necessarily mean clinical significance

9
Q

What is confounding?

A

When some factors other than the intervention or exposure under study, influence the overall outcome

10
Q

What are the ways we can help with confounding?

A

Randomization
Stratification
Matching

11
Q

What is randomization?

A

Ensures groups are similar in all aspects, known and unknown factors

12
Q

What is stratification?

A

Where we attempt to force an equal distribution of people from similar groups (Regina and Regina, Sask/Sask)W

13
Q

What is matching

A

Where we try and match people in the test/placebo group based on sex, age, and similar characteristics

14
Q

What is bias?

A

Problems with the way a study was designed conducted or analyzed that leads to incorrect results or conclusions

15
Q

What is selection bias?

A

Problems with how the study subject were selected

16
Q

What is information bias

A

Problems with measuing collecting or classifying information (Exposure and or outcomes)

17
Q

What does selection bias generally affect?

A

External validity

18
Q

Where do we see selection bias occur?

A

Self-seleciton/volunterr bias
Health workers bias
Attrition bias

19
Q

What are the two ways information bias can be categorized?

A

Outcome error
Exposure error

20
Q

What is outcome errors with respect to information bias?

A

RCT and observaiton studies where we have problems with measuring tools
Problems with actual measurements

21
Q

What is the exposure errors with respect to information bias

A

Problems with how subjects are categorized and problems with measuring tools

22
Q

What is an example of recall bias?

A

INdividuals remember things differentlu

23
Q

What is an example of interviewer bias?

A

24
Q

What is an example of surveillance/detection bias

A

One study group followed more closely than the other

25
Q

How do we deal with bias?

A

Recognize and acknowledge it

Standardization
Collect the same information form all subjects
blinding

26
Q
A