<p>I was reading through an <a href="http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2912019/#b1-0530278" rel="nofollow noreferrer">article</a> about research design. The authors gave an example on the relation between internal and external validity which I thought might be an important area of consideration when designing research proposals. </p>

<blockquote>
  <p>"A restricted study population (and exclusion criteria) may limit bias
  and increase the internal validity of the study; however, this
  approach will limit external validity of the study and, thus, the
  generalizability of the findings to the practical clinical setting.
  Conversely, a broadly defined study population and inclusion criteria
  may be representative of practical clinical practice but may increase
  bias and reduce the internal validity of the study."</p>
</blockquote>

<p>Broadly speaking, what questions can be asked to help decide one should strike a balance between the internal and external validity in our research proposal designs? Is it necessary then to carry out a pilot study first to establish some level of internal validity before moving on to establish external validity in a much bigger and formal follow-up study?</p>

<p>Crosspost: <a href="https://www.quora.com/Validity/What-tradeoffs-are-there-between-internal-and-external-validity" rel="nofollow noreferrer">Quora</a> </p>

<p>Update: This post has been shifted to <a href="https://academia.stackexchange.com/questions/59212/what-tradeoffs-are-there-between-internal-and-external-validity">academia.stackexchange</a>. All changes and edits will be made via the posting there henceforth.</p>

CC BY-SA 3.0
2017-05-05T19:47:08.537Z
For anyone tracking, it ended up [here](https://stats.stackexchange.com/questions/185609/what-tradeoffs-are-there-between-internal-and-external-validity)
mflo-ByeSE
CC BY-SA 3.0
2015-12-01T01:02:42.883Z
What does this have to do with cognitive science? Wouldn't http://academia.stackexchange.com/ be a much better place to ask this?
Izhaki
CC BY-SA 3.0
2015-12-02T02:22:06.173Z
Izhaki, thanks for the heads-up, will shift the post to academia.stackexchange.
Derrick Mah
CC BY-SA 4.0
2021-10-17T11:31:41.310Z
I’m voting to close this question because the was cross-posted (and has answers) at https://stats.stackexchange.com/questions/185609/what-tradeoffs-are-there-between-internal-and-external-validity
Chris Rogers
<methodology><experimental-psychology>
What tradeoffs are there between internal and external validity?
Derrick Mah
# What tradeoffs are there between internal and external validity?

(Asked by: username_0 on 2015-11-28)

I was reading through an [article](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2912019/#b1-0530278) about research design. The authors gave an example on the relation between internal and external validity which I thought might be an important area of consideration when designing research proposals.

> "A restricted study population (and exclusion criteria) may limit bias
> and increase the internal validity of the study; however, this
> approach will limit external validity of the study and, thus, the
> generalizability of the findings to the practical clinical setting.
> Conversely, a broadly defined study population and inclusion criteria
> may be representative of practical clinical practice but may increase
> bias and reduce the internal validity of the study."

Broadly speaking, what questions can be asked to help decide one should strike a balance between the internal and external validity in our research proposal designs? Is it necessary then to carry out a pilot study first to establish some level of internal validity before moving on to establish external validity in a much bigger and formal follow-up study?

Crosspost: [Quora](https://www.quora.com/Validity/What-tradeoffs-are-there-between-internal-and-external-validity)

Update: This post has been shifted to [academia.stackexchange](https://academia.stackexchange.com/questions/59212/what-tradeoffs-are-there-between-internal-and-external-validity). All changes and edits will be made via the posting there henceforth.

**Tags:** methodology, experimental-psychology

> **Comments:**
> **username_2**: What does this have to do with cognitive science? Wouldn't http://academia.stackexchange.com/ be a much better place to ask this?  
> **username_0**: username_2, thanks for the heads-up, will shift the post to academia.stackexchange.  
> **username_1**: For anyone tracking, it ended up [here](https://stats.stackexchange.com/questions/185609/what-tradeoffs-are-there-between-internal-and-external-validity)  
> **username_3**: I’m voting to close this question because the was cross-posted (and has answers) at https://stats.stackexchange.com/questions/185609/what-tradeoffs-are-there-between-internal-and-external-validity  

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## 0 answers

