Ttyjukl

Why aren't there more gauls like Obelix?

Can inspiration allow the Rogue to make a Sneak Attack?

Rationale to prefer local variables over instance variables?

Paper published similar to PhD thesis

The need of reserving one's ability in job interviews

Why is my explanation wrong?

Dukha vs legitimate need

How did Haman know Moshe Rabeinu's Yahrzeit but not his Birthday?

Why can't we use freedom of speech and expression to incite people to rebel against government in India?

I've given my players a lot of magic items. Is it reasonable for me to give them harder encounters?

Should we avoid writing fiction about historical events without extensive research?

Can a space-faring robot still function over a billion years?

How to write a chaotic neutral protagonist and prevent my readers from thinking they are evil?

Is it a Cyclops number? "Nobody" knows!

An Undercover Army

Affine transformation of circular arc in 3D

Quitting employee has privileged access to critical information

Should I use HTTPS on a domain that will only be used for redirection?

Has a sovereign Communist government ever run, and conceded loss, on a fair election?

Questions of the type "What do you think other people would think?"

Why would /etc/passwd be used every time someone executes `ls -l` command?

Are there other characters in the Star Wars universe who had damaged bodies and needed to wear an outfit like Darth Vader?

Was it really inappropriate to write a pull request for the company I interviewed with?

How does a sound wave propagate?

Are healthy patients an appropriate control group?

How to select a control / comparison group?How to analyze this pre-post control-intervention data set?Determining minimum required sample size for control (for purposes of measuring lift)Control group construction in Synthetic Control MethodDynamic treatment timing in a panel-DiD frameworkAnalysis of pre-post treatment data with changes over timeanalytical methods for crossover study that has an addition control groupStatistical test to use?Making a control group out of a linear combination of possible control groupsControl group selection

2

$begingroup$

I am working on a study where patients with a chronic disease received a treatment. The goal is to determine the effect of the treatment on various outcome variables. I have pre and post data (before and after the treatment) for the sick patients and also for a control group of patients who are healthy. It would have been considered unethical to withhold treatment from sick patients, hence there was no control group of sick patients who did not receive the treatment.

I plan to analyze the data using linear mixed effects models. I’ve seen examples of how to analyze this type of data when you have pre/post data with a control group, for example including variables in the model such as the time point, whether the individual is in the treatment or control group, and the interaction between the two.
However, I’m wondering about the appropriateness of this approach when the control group is healthy patients. Does it really make sense to make comparisons to a healthy group in this way when the goal of the study is to determine what effect the treatment had? By making comparisons to a group of healthy patients, is this answering a different question?

Appreciate any comments. thank you!

control-group treatment

share|cite|improve this question

asked 5 hours ago

LauraLaura

163

$endgroup$

add a comment | 

2

$begingroup$

I am working on a study where patients with a chronic disease received a treatment. The goal is to determine the effect of the treatment on various outcome variables. I have pre and post data (before and after the treatment) for the sick patients and also for a control group of patients who are healthy. It would have been considered unethical to withhold treatment from sick patients, hence there was no control group of sick patients who did not receive the treatment.

I plan to analyze the data using linear mixed effects models. I’ve seen examples of how to analyze this type of data when you have pre/post data with a control group, for example including variables in the model such as the time point, whether the individual is in the treatment or control group, and the interaction between the two.
However, I’m wondering about the appropriateness of this approach when the control group is healthy patients. Does it really make sense to make comparisons to a healthy group in this way when the goal of the study is to determine what effect the treatment had? By making comparisons to a group of healthy patients, is this answering a different question?

Appreciate any comments. thank you!

control-group treatment

share|cite|improve this question

asked 5 hours ago

LauraLaura

163

$endgroup$

add a comment | 

$begingroup$

I am working on a study where patients with a chronic disease received a treatment. The goal is to determine the effect of the treatment on various outcome variables. I have pre and post data (before and after the treatment) for the sick patients and also for a control group of patients who are healthy. It would have been considered unethical to withhold treatment from sick patients, hence there was no control group of sick patients who did not receive the treatment.

I plan to analyze the data using linear mixed effects models. I’ve seen examples of how to analyze this type of data when you have pre/post data with a control group, for example including variables in the model such as the time point, whether the individual is in the treatment or control group, and the interaction between the two.
However, I’m wondering about the appropriateness of this approach when the control group is healthy patients. Does it really make sense to make comparisons to a healthy group in this way when the goal of the study is to determine what effect the treatment had? By making comparisons to a group of healthy patients, is this answering a different question?

Appreciate any comments. thank you!

control-group treatment

share|cite|improve this question

asked 5 hours ago

LauraLaura

163

$endgroup$

share|cite|improve this question

asked 5 hours ago

LauraLaura

163

share|cite|improve this question

asked 5 hours ago

LauraLaura

163

asked 5 hours ago

LauraLaura

163

asked 5 hours ago

LauraLaura

163

1 Answer
1

active

oldest

votes

2

$begingroup$

This makes no sense to do because the average outcome of the healthy patients is meant to stand in for the average outcome of the sick patients had they not received treatment (which is not observed due to the fundamental problem of causal inference/unbearable lightness of being).

Without some additional strong assumptions, there is not much else you can do with this design. The difference-in-differences approach you outline above assumes that the sick when untreated share a trend with the healthy (though there may be a constant gap between them), which seems unlikely to hold.

share|cite|improve this answer

answered 3 hours ago

Dimitriy V. MasterovDimitriy V. Masterov

20.9k14094

$endgroup$

add a comment | 

Your Answer

StackExchange.ifUsing("editor", function () {
return StackExchange.using("mathjaxEditing", function () {
StackExchange.MarkdownEditor.creationCallbacks.add(function (editor, postfix) {
StackExchange.mathjaxEditing.prepareWmdForMathJax(editor, postfix, [["$", "$"], ["\\(","\\)"]]);
});
});
}, "mathjax-editing");

StackExchange.ready(function() {
var channelOptions = {
tags: "".split(" "),
id: "65"
};
initTagRenderer("".split(" "), "".split(" "), channelOptions);

StackExchange.using("externalEditor", function() {
// Have to fire editor after snippets, if snippets enabled
if (StackExchange.settings.snippets.snippetsEnabled) {
StackExchange.using("snippets", function() {
createEditor();
});
}
else {
createEditor();
}
});

function createEditor() {
StackExchange.prepareEditor({
heartbeatType: 'answer',
autoActivateHeartbeat: false,
convertImagesToLinks: false,
noModals: true,
showLowRepImageUploadWarning: true,
reputationToPostImages: null,
bindNavPrevention: true,
postfix: "",
imageUploader: {
brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
allowUrls: true
},
onDemand: true,
discardSelector: ".discard-answer"
,immediatelyShowMarkdownHelp:true
});


}
});

draft saved

draft discarded

Sign up or log in

StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});

Sign up using Google

Sign up using Facebook

Sign up using Email and Password

Post as a guest

Name

Email

Required, but never shown

StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fstats.stackexchange.com%2fquestions%2f396288%2fare-healthy-patients-an-appropriate-control-group%23new-answer', 'question_page');
}
);

Post as a guest

Name

Email

Required, but never shown

2

$begingroup$

This makes no sense to do because the average outcome of the healthy patients is meant to stand in for the average outcome of the sick patients had they not received treatment (which is not observed due to the fundamental problem of causal inference/unbearable lightness of being).

Without some additional strong assumptions, there is not much else you can do with this design. The difference-in-differences approach you outline above assumes that the sick when untreated share a trend with the healthy (though there may be a constant gap between them), which seems unlikely to hold.

share|cite|improve this answer

answered 3 hours ago

Dimitriy V. MasterovDimitriy V. Masterov

20.9k14094

$endgroup$

add a comment | 

2

$begingroup$

This makes no sense to do because the average outcome of the healthy patients is meant to stand in for the average outcome of the sick patients had they not received treatment (which is not observed due to the fundamental problem of causal inference/unbearable lightness of being).

Without some additional strong assumptions, there is not much else you can do with this design. The difference-in-differences approach you outline above assumes that the sick when untreated share a trend with the healthy (though there may be a constant gap between them), which seems unlikely to hold.

share|cite|improve this answer

answered 3 hours ago

Dimitriy V. MasterovDimitriy V. Masterov

20.9k14094

$endgroup$

add a comment | 

$begingroup$

This makes no sense to do because the average outcome of the healthy patients is meant to stand in for the average outcome of the sick patients had they not received treatment (which is not observed due to the fundamental problem of causal inference/unbearable lightness of being).

Without some additional strong assumptions, there is not much else you can do with this design. The difference-in-differences approach you outline above assumes that the sick when untreated share a trend with the healthy (though there may be a constant gap between them), which seems unlikely to hold.

share|cite|improve this answer

answered 3 hours ago

Dimitriy V. MasterovDimitriy V. Masterov

20.9k14094

$endgroup$

share|cite|improve this answer

answered 3 hours ago

Dimitriy V. MasterovDimitriy V. Masterov

20.9k14094

answered 3 hours ago

Dimitriy V. MasterovDimitriy V. Masterov

20.9k14094

answered 3 hours ago

Dimitriy V. MasterovDimitriy V. Masterov

20.9k14094