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...
View ArticleIncluding an interaction variable which doesn't vary within a key control...
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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According to DAG theory, why controlling for this variable doesn't close the...
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.I...
View ArticleWhat analysis do I do? (Wage, education, gender)
I'm doing research on pay in function of degree (master vs. doctorate) and gender (man vs. woman).My research consists of 1 dependent variable: salary (salary varies from 210 euro to 12.000 euro in...
View ArticleMultiple 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...
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How do you control for a variable in SEM with mediation? What do I regress...
I have an SEM model that tests for mediation. There is 1 independent variable, 1 mediator, and 2 dependent variables. All these variables are continuous.I want to control for the following variables:...
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Controlling for a variable when estimating interaction effects
Consider the relationships among four variables: sex, activity, height, and weight, as depicted below:Suppose that weight is the response variable. When sex serves as the predictor, there is no need to...
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Serial multiple mediated model in lavaan not calculating standard errors,...
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 the...
View ArticleWhen 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...
View ArticleWhat 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?
View ArticleWhat is an intuitive explanation for a lay-person why controlling for a...
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 collider...
View ArticleUsing interaction terms in causal models
I have the following model:LOS (length of stay) = b0 + b1 Age + b2 Gender + b3 BMIwhere Age and Gender are control variables, and my main IV is BMI. And this model isn't made for predictive purpose; we...
View ArticleHow to check for relevant covariates in difference-in-difference regression?
I am conducting a diff-in-diff regression over two periods of time with the treatment in between. Next to the dummy variable time ('Post'), I have 3 groups for the other variable and therefore 2 dummy...
View ArticleCan we isolate the effect of two different control variables in a...
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 we...
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Is it meaningful to control for variables that are correlated with the...
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 are correlated...
View ArticleIs there a technique similar to multiple regression which does not require...
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 gene...
View ArticleDo control variables need to have a correlation to both the independent...
I have been wondering about this: Do control variables need to have a correlation to both the independent variable and the dependent variable?E.g. I want to check the effect of Education (independent...
View ArticleANOVA/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 (EnergykJT0 and...
View ArticleHow 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...
View ArticleQuestion 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...
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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 participants is...
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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...
View ArticleAdding 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...
View ArticleCan 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...
View Articlerandomisation 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...
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Inlcuding grouping controls, which are based on the explanatory variabels, in...
BackgroundI 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...
View ArticleIs 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...
View ArticleRegression 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?...
View ArticleRunning 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...
View ArticleDifference between controlling for other variables in additive models vs....
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 alcohol...
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