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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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Can I interpret the size of my regression coefficient when I only control for confounders and not non-confounding covariates?

I am very confused at the moment, for my bachelor's thesis I am performing a Panel Individual Fixed Effects analysis and have only controlled for confounders. I was under the assumption that when I ...
user418117's user avatar
8 votes
3 answers
543 views

Comparison of 2 groups with covariate

I compared 2 groups and found that their test scores are significantly different. However, I also found that they are significantly different in the mean age. I want to see if the scores between the ...
user3315563's user avatar
4 votes
1 answer
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Running a Negative Binomial Regression with Overdispersion

I am not an expert on SPSS but have been developing my skills and believe I should run a negative binomial regression on my data, though I am not certain. I am testing the number of days people go ...
Vito's user avatar
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2 votes
1 answer
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Regression in sex differences multiple dependent variables

If I want to examine sex differences in three variables, lets say academic attainment, study motivation, and a variable that is categorical. How should can I fit these variables with OLS regression? ...
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Is every fixed effect a factor in the model?

Participants received one of three sets of instructions and each completed the same two unique questions in a randomized order. I have a 3 (instructions type) x 2 (question) mixed effects model with ...
statsexplorer2024's user avatar
1 vote
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26 views

Inlcuding grouping controls, which are based on the explanatory variabels, in a random effects model

Background I have (unbalanced) panel data of a set of agricultural firms. I am attempting to estimate the effect of the surface area of crops (wheat, potatoes, onions, sugar-beets, corn) on the fixed ...
Tom's user avatar
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1 vote
1 answer
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randomisation issue/crisis

I have randomized into three groups using a randomization aid and groups were examined at 2 time points. however in the analysis found that there was a significant difference at baseline in one of the ...
ketchup28's user avatar
2 votes
1 answer
47 views

Can covariates be included in multiple regression?

I am interested in understanding if two predictors variables are associated with treatment outcome (DV). I included two covariates that 1) differed across my levels of IV (age) and 2) another that is ...
Erika's user avatar
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3 votes
1 answer
281 views

Multicollinearity and control variables dilemma

I had some superficial understanding of multicollinearity, that two highly correlated variables in the regression model are not what we want, as the estimated coefficient would be biased. Control ...
LJNG's user avatar
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3 votes
1 answer
69 views

Multilevel Modeling and Alternatives for Repeated Measures Design

I am conducting a study on the effect of different characteristics of urban space on human physiological response. The study is a "repeated measures" design. For this example, each of 5 ...
Mark S.'s user avatar
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Question regarding control variables in a serial mediation model

i encountered questions regarding running a serial mediation model in mplus. my IV is ERS(excessive reasssurance seeking) DV is depression (DEP), my proposed two mediators are INU (internet use) and ...
Claire Cheng's user avatar
1 vote
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How do I regress income quartiles against each other?

I'm looking to find out whether an attitude differs across income quartiles. My supervisor has mentioned dummy coding and regressing the quartiles against each other, however, I'm sort of at a loss as ...
Lucy S's user avatar
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ANOVA/ANCOVA results in SPSS

I am unsure about how to interpret the output box I get doing an ANOVA in SPSS. That's the "Tests of between-subject effects" box in particular. I had 2 groups (A and B), and 2 results (...
Rene's user avatar
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6 votes
2 answers
229 views

Is there a technique similar to multiple regression which does not require linearity?

Background: We have biological gene expression data of cells (from a single-cell experiment). So, the data is in the form of a gene by cell matrix, where each value is the expression of a specific ...
Sam's user avatar
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5 votes
0 answers
92 views

Is it meaningful to control for variables that are correlated with the independent and dependent variables?

Statistical training from the National Institute of Child Health and Human Development states: A general (usually unquestioned) assumption is that differences on "nuisance" variables that ...
Mohan's user avatar
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Using interaction terms in causal models

I have the following model: LOS (length of stay) = b0 + b1 Age + b2 Gender + b3 BMI where Age and Gender are control variables, and my main IV is BMI. And this model isn't made for predictive purpose; ...
Hussain's user avatar
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1 answer
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What is an intuitive explanation for a lay-person why controlling for a collider is bad practice while controlling for a confounder is good practice?

Cinelli et al., 2022 and Wysnocki et al., 2022 describe in technical terms how controlling for a collider can lead to biased estimates. If one needs to explain why one should not control for a ...
JElder's user avatar
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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?
TylerDurden's user avatar
4 votes
1 answer
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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 ...
Patrick Nicodemus's user avatar
1 vote
0 answers
24 views

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 ...
Cecilia Sada's user avatar
2 votes
1 answer
61 views

Controlling for a variable when estimating interaction effects

Consider the relationships among four variables: sex, activity, height, and ...
bluepole's user avatar
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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 ...
João Machado's user avatar
4 votes
2 answers
226 views

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....
robertspierre's user avatar
1 vote
0 answers
12 views

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 ...
Hadar's user avatar
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3 votes
1 answer
106 views

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 ...
Muller I. 's user avatar
1 vote
1 answer
78 views

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 ...
chunguc1004's user avatar
1 vote
0 answers
49 views

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 ...
Tim's user avatar
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1 vote
1 answer
59 views

What makes a good control variable?

I am currently studying whether academic freedom (independent variable) has an impact on university rankings (dependent variable). So far, my model is only composed of these two variables, as well as ...
Muller I. 's user avatar
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0 answers
72 views

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'...
chunguc1004's user avatar
2 votes
1 answer
40 views

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 ...
Lily RR's user avatar
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1 vote
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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 ...
Patrick Nicodemus's user avatar
2 votes
0 answers
268 views

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 ...
Ploit88's user avatar
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1 vote
1 answer
303 views

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 ...
Y45H's user avatar
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0 votes
1 answer
165 views

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 ...
Sarah's user avatar
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-1 votes
1 answer
45 views

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 ...
Catalin's user avatar
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7 votes
2 answers
875 views

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 ...
sean.mcgrath's user avatar
7 votes
2 answers
564 views

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 ...
Anthony's user avatar
  • 540
1 vote
2 answers
156 views

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 ...
Thao Truong's user avatar
2 votes
1 answer
278 views

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 ...
Larissa Cury's user avatar
2 votes
0 answers
28 views

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 ...
Janet Johnson's user avatar
1 vote
1 answer
50 views

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....
Juliette's user avatar
5 votes
2 answers
759 views

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 ...
sean.mcgrath's user avatar
1 vote
0 answers
72 views

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 ...
willie's user avatar
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1 vote
1 answer
223 views

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 ...
LeCV's user avatar
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1 vote
0 answers
564 views

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 ...
TFT's user avatar
  • 345
1 vote
0 answers
48 views

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 ...
Abdel Kdj's user avatar
3 votes
1 answer
2k views

Adding Controls to Staggered Difference-in-Difference Regressions in 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 ...
Santi Beans's user avatar
0 votes
0 answers
117 views

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 ...
Rgf's user avatar
  • 1
1 vote
0 answers
495 views

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 ...
Macaulay's user avatar
0 votes
1 answer
246 views

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 ...
Dilara's user avatar
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