Hi,
I have answered some questions for some homework and I've got one of them wrong. I cannot modify my answer but I would really love to know why my answer is wrong.
This is the statement of the problem:
n this series of questions, we examine data from a study of 158 infants who visited Northbay Healthcare in Solano County, California for a Vitamin K shot. Assume that the infants in the study are a representative random sample from all infants in Northbay Healthcare.
Nurses administered a Vitamin K shot to each infant. Infants were randomized to two different protocols to study how to reduce pain experienced by the infants due to the shot. The infants were divided into two groups – the control group, where standard protocol for handling the infants was used; and an intervention group, where mothers held their infants prior to, during, and after administration of the shot. Pain was measured using the Neonatal Infant Pain Score (NIPS) (Lawrence et. al 1993). The variables in the dataset are described below:
id – unique identifier for each infant
group – 1 if intervention group, 0 if control
pain0 – NIPS score 0 seconds after shot
pain30 – NIPS score 30 seconds after shot
pain60 – NIPS score 60 seconds after shot
pain120 – NIPS score 120 seconds after shot
crytime – total time that the infant cried in seconds
And the question:
Assuming randomization was successful and all participants complied with their assigned exposure, which of the following should we be concerned about:
Confounding by sex of the infant
Confounding by the amount of pain experienced by the infant
Effect modification by sex of the infant
Misclassification of the exposure status of the infant
My answer was:
Confounding by the amount of pain experienced by the infant
Could anyone help me reason why I am wrong?
Thanks!
Your answer is nuts. Reason? I am wondering if you know what a confounding variable is? It is something that has a relationship to the independent variable, thus may be related to the dependent variable.
Your answer, the amount of pain, is the dependent variable NIPS score. You need to be searching for something that may be related to the kids getting the shot, or how much pain the registered.
Did boys get the shot more frequently than girl infants? Do boy babies whine more than girls getting a shot? (confounding by gender of infant)
(confounding by effect modulation)
Hi Bobpursley,
Thank you very much for your answer...
The problem is that I do not have any data on whether the boys got shots more frequently than girls enfants or whether boy babies whine more than girls...
I guess those could be an explanation if I had more data...
Would be misclassification an unreasonable answer as well?
Thanks for your help, I really want to understand the topic. :-)
To determine why your answer is wrong, let's first understand the meaning of the terms mentioned in the question.
Confounding: Confounding occurs when the relationship between two variables is distorted or influenced by a third variable. In other words, the observed association between two variables may be due to the influence of a third variable rather than a direct causal relationship.
Effect Modification: Effect modification, also known as interaction, refers to a situation where the effect of one variable on an outcome is modified by another variable. In other words, the relationship between two variables is not the same across different levels of a third variable.
Misclassification: Misclassification refers to incorrectly assigning individuals to certain categories or groups. This can happen due to measurement error or other factors leading to incorrect classification.
Based on the information provided in the problem, the infants were divided into two groups - the intervention group and the control group. The intervention group involved the mothers holding their infants prior to, during, and after the administration of the Vitamin K shot. The control group followed the standard protocol for handling the infants.
Now, let's analyze the options provided:
Confounding by sex of the infant: The sex of the infant is not mentioned as a factor in the assignment or treatment groups. Since the assignment of infants to the intervention or control group was randomized, it is unlikely that the sex of the infants would act as a confounder in this scenario. Therefore, this option can be eliminated.
Confounding by the amount of pain experienced by the infant: This option seems plausible because the pain experienced by the infants might differ between the intervention and control groups, introducing confounding. However, it is important to note that the question states, "Assuming randomization was successful and all participants complied with their assigned exposure." This implies that randomization should have balanced the pain experience across the groups. Therefore, we can eliminate this as a concern in this context.
Effect modification by sex of the infant: Similar to the first option, the sex of the infant is not explicitly involved in the assignment or treatment groups. Therefore, effect modification by sex is less likely to be a concern in this scenario. We can eliminate this option.
Misclassification of the exposure status of the infant: Misclassification refers to incorrect assignment of individuals to certain groups. In this context, misclassification could refer to situations where infants were assigned to the wrong group (intervention or control) by mistake. However, the question assumes that all participants complied with their assigned exposure. Since the compliance is assumed to be high, misclassification is less likely to be a concern.
To summarize, based on the information provided and the assumptions made in the question, the option "Confounding by the amount of pain experienced by the infant" is not a significant concern. The randomization of participants and the assumption of high compliance should account for any potential confounding by the amount of pain experienced by the infants.