10.1: Internal & External Validity ✅

Question 1

Interprofessional education quote

Answer 1

“2 or more professions learn about, from and with each other
-to enable effective collaboration and improve health outcomes”

Clinical and Public Health requires multi-disciplinary team

Question 2

Internal Validity

Answer 2

• Are the results valid in terms of the truth in the source population?
• Exposure/outcome association or are the results explained by something else?

Question 3

External Validity

Answer 3

• Can our results be generalized to the general population or to other similar populations?

Question 4

Internal Validity

Answer 4

Our the results influenced by:

1) Chance

2) Bias

3) Confounding

Question 5

Chance

Answer 5

Due to random nature of sampling, random error will be an important role in results

Any estimate is subject to chance

Any findings could potentially be a chance finding

This is determined by the p-value and 95% confidence interval

Question 6

How do you determine if the validity of results affected by chance?

Answer 6

Check statistical significance

If statistically significant, in can be concluded with relative safety that the findings aren’t due to chance

Question 7

How do you minimise the influence of chance

Answer 7

Take a large, representative sample to:
-reduce standard error and
-increase the power of the study

Question 8

Selection bias

Answer 8

Errors in the process of sampling which result in selecting a non-representative sample

-and consequently any derived estimate will likely be biased (e.g., sampling bias, etc.)

Question 9

Information bias

Answer 9

Errors in the process of data collection, which result in: -inaccurate assessment of the exposure and/or outcome variables
(e.g., recall bias, interviewer bias, etc.)

Question 10

How do we determine if the results are affected by bias?

Answer 10

Not always easy to determine

Researcher needs to use their reflection and self-criticism

Samples using convenience sampling and measurements resulting from participant self-reports should always be expected to be suffering from bias

Question 11

How to minimise the influence of bias?

Answer 11

Choose sample representative of the source (minimise selection bias)

Use tools that have high accuracy (minimise information bias)

Making a thorough investigation of the accuracy of the data collected (data cleaning)

Question 12

What can Compounding greatly compromise?

Answer 12

The validity of a study
-by distorting the estimate of a potential association and even lead to masking a true association

-making a false association ‘appear’, when no true association exists.

Question 13

How do we determine if results are affected by confounding?

Answer 13

Non-experimental conditions should expect to be affected

Consider confounding if an unexpected result or if there is something doesn’t make sense biologically

Question 14

How to minimise the influence of confounding?

Answer 14

Make a list of potential confounders

Adjust for the potential confounders during data analysis

Be cautious of residual confounding

Question 15

External validity

Answer 15

Interested in whether our findings can be generalized to:
1.The general population
2. Other similar populations

Question 16

How to determine whether our results have low external validity?

Answer 16

Matter of correct judgment of the researcher

Whether sample is representative or not of the general population or similar populations in other countries

-going through the literature and investigating the evidence on the association of interest is always very helpful for evaluating the external validity of our findings

*we should never assume that our findings are externally valid without careful thought and investigation first

Question 17

How to improve external validity?

Answer 17

Avoid highly selected samples if we want to generalize our results to the general population.
-choosing a random sample is the ideal approach If we have intentionally chosen a population with specific characteristics

Our sample accurately represents the specific population sub-group In such a case:
-generalizations to the general population should be avoided
-generalizations to other similar populations could be done but always under certain assumptions

Question 18

Note on internal and external validity
-apart from one of the criteria of internal validity (chance)

Answer 18

Everything else related to judging the internal and external validity of a study is somewhat subjective in nature and requires:
-experience,
-critical thinking, and
-informed judgment from the researcher.

Question 19

What must be done before deriving conclusion and generalizing research findings?

Answer 19

Thoroughly examine and confirm both internal and external validity of the relevant research studies

Question 20

What must you do with evidence before you use it in clinical practice?

Answer 20

Examine the evidence critically

Question 21

What happens when you work together with the multidisciplinary team?

Answer 21

Results in optimal patient and community care