Exam Q7

Exam Q7

by Jean Digitale -

"Do you agree with the authors conclusions in this study? Is there a potential for residual confounding? Please explain your answer including a DAG and interpret each of the additional paths using D-separation terminology. Provide at least one suggestion of what you might change if you were to improve on this study and explain."

For this question, are we supposed to only include "additional paths" that are residual confounding (if we think it is present)? Or are we supposed to include any "additional paths" that affect whether we agree with the authors' conclusions?

Not sure how complicated to get with the DAG...

Thanks,

Jean

Re: Exam Q7

by Sandeep Brar -

Would you like us to draw a DAG for beta-carotene or all of the supplements? The authors adjusted for different confounders for beta-carotene. Thanks!

Sandeep

Re: Exam Q7

by June Chan -

Hi Sandeep, 

You can focus on "all of the supplements" and the confounding factors addressed in the majority of the main analyses. As mentioned in response to Jean's question, please be sure to address the residual confounding question and anything you'd do to improve the study with regards to bias due to confounding. 

You are welcome to also critique or comment on the beta-carotene specific analyses if you wish, or if this is part of your topic that you would "improve".

Hope that clarifies. 

best, 

June

Re: Exam Q7

by June Chan -

Hi Jean, 

Please answer this question by addressing the additional paths you would consider for addressing residual confounding.  With regards to what one could improve, please include some comment on confounding/residual confounding. You are welcome to also comment on other things one might do to improve the study (via your DAG), but the theme of this question is on confounding and what we can understand about confounding from a DAG. Please be sure to label and explain your DAG and the assumptions. 

With regards to how complicated to get - I'd focus on their major research question, and practical critiques, given the study type, study population, and design. There are always things one can do to improve a study with unlimited funds or time, so I'd focus on things that they could have done within a reasonable additional effort.

Hope that clarifies. 

Best, 

JMC