Questions tagged [controlling-for-a-variable]
A control variable is one which is included in a model primarily for its impact on the total model rather than for its own substantive interest.
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Best practice for comparing data between completers and non-completers?
I conducted a study which collected data on a brief one-time intervention at 3 timepoints (pre, post, and one-week follow-up). There were some participants who dropped out between these 3 timepoints. ...
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What is an “independent” effect?
According to one study by Wang and colleagues (2013), smoking cigars has “a positive and independent” effect on testosterone. What is an independent effect and what is the significance of one?
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When is "controlling for" effects nonsensical?
I am not as knowledgeable about statistics as I would like and I am looking for resources to help me understand what kinds of questions are meaningful and which are nonsensical. We are developing some ...
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Serial multiple mediated model in lavaan not calculating standard errors, Z-values, and P values for defined parameters
I am trying to run the following model in Lavaan, in which AM, RM, and CU are latent variables. It also has three control variables (CV1, CV2, and CV3).
I have written the code that is included at ...
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Controlling for a variable when estimating interaction effects
Consider the relationships among four variables: sex, activity, height, and ...
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Multiple proportion test
I want to test which week day is more important for a specific client, given a historical communication in different days and with open email or not . for example:
monday
Tuesday
Wednesday
...
email
...
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According to DAG theory, why controlling for this variable doesn't close the backdoor path opened by controlling for the collider?
I have made the following model in DAGitty:
Where $X_2$ is controlled for.
DAGitty says:
The total effect cannot be estimated due to adjustment for an intermediate or a descendant of an intermediate....
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Including an interaction variable which doesn't vary within a key control variable
Let’s say we want to check the effect of the interaction of education level and gender of the salesperson on number of units sold by them. We have thousands of sales people in the data, but they only ...
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Exogeneity Check of Control Variables? Covariance
I have performed an exogeneity check on my control variables to assess their validity before incorporating them into my regression analysis. Upon conducting the analysis, I observed a significant ...
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Is it a bad idea to use a variable that is strongly correlated with my independant variable of interest as a control variable?
I am currently looking into the correlation between academic freedom (my independant variable) and university rankings (my dependant variable) using OLS.
I find a negative significant correlation, but ...
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Logic of including an interaction term as a control variable?
I am reading a paper and it has the following simple model:
Y = a + b1 + b2 + b1*b2 + e.
The author seems to be interested in b1, not the interaction term.
How do we interpret b1 in this case? I'm a ...
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How to account for data's margins of error in a regression?
Apologies if this is too simple of a question. I work with population data from the census, which provides a margin of error for all their variables. Reviewers have asked that I account for the MOE in ...
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Control variables in interaction effects [duplicate]
I'm new to econometrics and this might be a dumb question.. but if I were to include an interaction term, do I also have to input the variables separately as a control variable?
For example, Y = a + ...
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What makes a good control variable?
I am currently studying whether academic freedom (independant variable) has an impact on university rankings (independant variable). So far, my model is only composed of these two variables, as well ...
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How does R know which variable is the main variable of interest?
I'm starting to get a little confused about how R knows which variable is the main variable and which others are simply controls. For example, let's say there are three variables Y, X1, and X2, and I'...
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Influence of demographics/background on part worth utilities in conjoint analysis
I’m currently working on a conjoint analysis (CBC) about e-commerce fulfillment. The idea is to find out (among other things) whether customer characteristics (gender, age, home-presence, …) influence ...
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Testing implications of Conditional Mean Independence
In some empirical studies as a validation exercise some people regress some variables on the variable of interest controlling for key control variables. The reason for doing this I think comes from ...
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Test the parallel trend assumption in DiD regression with controls
I am running a DiD regression to evaluate the effect of a policy and I want to check whether the parallel trend assumption holds in my data. However, the model includes control variables that can ...
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Controlling parents education that correlates with each other
I want to include both parent's education variables as control variables in my estimation about the effects of maternal bargaining power to child's educational attainments. They are stated as ...
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Does the scale of a control variable matter?
why does the effect of a control variable on the coefficient of interest depends on how the control variable is measured?
The following DiD model is estimated:
Y = beta_1Treat + beta_2Post + beta_3(...
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Does it make sense to "regress out on one variable" during permutation testing?
In our lab we have developed a non parametric permutation test which assesses whether a feature $f:G\to \mathbb{R}$ respects a given symmetric binary relation $A\subset G\times G$.
Regard $A$ as being ...
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Why add control variables in the second stage of an IV regression?
I am reading an article on the effect of income on energy choice (e.g., choice between traditional sources such as charcoal and modern ones such as electricity).
The authors instrument income with ...
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Difference between controlling for other variables in additive models vs. interaction model
In a regression model with multiple predictors, the word "control" is used to refer to the inclusion of other variables than the one relevant to a specific question (e.g., the effect of ...
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Controlling for individual differences in a repeated-measures design?
I have been analysing a study where around 500 participants each were given a survey, so there were repeated measurements of each participant. Participants were male and female uni students who were ...
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Controlling for influential/leverage/outliers data points in multiple regression in R lm() -- add a new variable to specify points?
hoping someone will be able to help me here.
I have a dataset that contains some outlying, influential data points. These data are definitely accurate and represent real measurements. Example 1, one ...
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Dependent variable "controlled" by a binary variable?
in my research the DV should be measured by means of an intent scale (Individual Entrepreneurial Intent Scale). For "controlling" if the answer in DV is correct, I want to include a binary ...
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Can age ever be confounded if it is the independent variable in an observational study?
This is a follow-up to my previous question: "Basic understanding of control variables in observational studies"
I have understood the answer, but am still trying to figure out what I think ...
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How to conduct Regression Analysis within an intervention scenario, including control variables, in R?
I am conducting a case study on a 1000 patients, monitoring the effect of a medication (intervention). I want to see how their average blood sugar is impacted by the intervention. Along with the ...
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How to transform a dependent variable to control for independent variables?
I have a dependent variable, the scale and location of which varies significantly when grouping by the values of a few key independent variables. As a result, when grouping the dependent variable by ...
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Can we just "pre-test" the backdoor criterion?
I am trying to use DAGs to think more carefully about my regression models. I have a question about the "backdoor criterion", as usually seen in the DAG below (we are interested in the ...
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diff-in-diff at indiv level with controls at family level - I think I need cluster-robust st. errors but not sure how to code (sas)
I'm using claims data and plan selection is assoc with family level variables as that's the level at which a plan is selected. I want to control by these variables in the diff-in-diff for number of ...
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MANOVA (SPSS) test - determine control variables in moderation analysis
I am examining the moderating effect of IV1 in the relationship between IV2 and DV using hierarchical regression analysis. The study has 2 demographic variables: gender and age. To determine if it is ...
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Can we isolate the effect of two different control variables in a semi-partial correlation?
I know that we are able to use a partial correlation when we want to correlate X and Y but Z affects both of them and that we may use a semi-partial correlation when we want to correlate X and Y and ...
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How to study the impact of time in a mixed-factorial design?
I ran a study to compare 2 different computer interfaces (say A and B) meant to be used in an unfamiliar environment.
I want to compare:
How much effort participants took to complete a certain task ...
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Controlling for an effect by adding it as covariate in R
I have a dataset like this:
individual1
individual2
Bray_Curtis
Dyad_type
proximity
matriline
id1
id2
Aapi
App
0.47
1
0.14
1
1
2
Aapi
Eis
0.60
2
0.03
0
1
4
Potj
Popp
0.50
1
0.11
1
3
5
Aapi
Potj
0....
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Basic understanding of control variables in observational studies
I'd like to understand the basic logic for control variables in observational studies.
According to Wikipedia, one should control for confounding variables, which "in this context means other ...
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Is there a formal methodology for controlling a variable in a tree based model?
I am currently building a xgboost model to classify data into 6 categories of risk for insurance policies. I have 5 years worth of policy holder data, including policy year. When building a GLM for a ...
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Data points for some control variables missing in regression - still feasible?
I'm currently working on an event study to examine abnormal returns.
In the first step, I've calculated abnormal returns in regards to a certain type of company event, consisting of roughly 13,000 ...
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Are control variables always exogenous?
My professor said that control variables are generally thought to be exogenous in an OLS context, i.e. uncorrelated with the main independent variable in my regression. However, I think that they are ...
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Panel Data with 2 IV and 1 DV
I am working on my thesis and I have a few questions about which method I should use for the analysis of my data.
My research is about inequality in Europe, and in general households in Europe that ...
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Adding Controls to Staggered Difference in Difference Regressions on Stata
I am running a staggered diff-in-diff model, looking at legalization's effect on various variables. For context, only a percentage of all states have legalized, and the year they legalized differs ...
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How to compare more than 2 groups on the group rate?
I need to compare more than 2 organizations on the number of events each has, controlling for the number of buildings. The number of events per organization is small (0 - 6) and the number of ...
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When do control variables increase precision?
Suppose we're interested in the effect $\beta$ of a treatment $D$. To increase the precision of our estimate (ie., reduce the variance of $\hat{\beta}$), we can include a control variable $X$ that ...
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Controlling for time elapsed between baseline and treatment
I'm having a mixed model with 5 repeated measurements (time is categorical because the timepoints represent discrete events).
Edit: I have 5 meaningful timepoints: t0 baseline (neutral timepoint); t1 ...
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Multiple regression - conceptual questions
Problem statement:
I'm working on a multiple regression after running an RCT, to confirm treatment effectiveness and quantify effect size. Initially, when I regressed a dependent variable against some ...
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Mediation/moderation: when interested in the effects of X on Y, should I leave my mediator/moderator(+interaction) in the analysis?
If I am running a mediation analysis (X: independent; Y: dependent; M: mediator; also applies to moderation), but I am also interested in the simple correlation between X and Y (i.e., for my first ...
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controlling for a categorical variable
I am performing a regression and have multiple control variables such as Religion, Caste, Highest Education of Adult in the Household, and Income Source. This might be an easy question but I was a bit ...
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Controlling for non-linear variable in non-linear modeling of response
I need to model a continuous response variable $y$ based on continuous features $x_1, ..., x_n$ while controlling for another continuous feature $x_c$. The intent is to understand how much an increase ...
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When is a Control a Bad Control Exactly
Hi just had a short question. If a control variable is caused by another control variable would that make it a bad control? I know control is bad if it is the direct outcome of the treatment but in ...
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Interaction control variables in a difference-in-difference regression
I have a question with regards to control variables in a difference-in-difference regression. I would like to know the difference between including single control variables and including control ...
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