Questions tagged [interaction]

A situation where the effect of an explanatory variable may depend on the value of another explanatory variable.

Filter by
Sorted by
Tagged with
0
votes
0answers
47 views

Unexpectedly large coefficients in logistic interaction model

I would like to know if you could provide any insights regarding large and unexpected coefficients in logistic models with interaction terms. When running the interaction model, the coefficients for ...
0
votes
0answers
7 views

Multi level logistic regression with ordinal level dependent and independent variables

I am currently trying to run a multi level logistic regression model and struggling to identify the best way forward using STATA.Details below: Independent variable: ordinal with 5 levels Dependant ...
0
votes
0answers
27 views

Is it necessary to adjust for multiple comparisons (e.g. Bonferroni) when using continuous interaction terms (e.g. age)?

I am interested in analyzing how the effect of a dichotomous variable on a dichotomous outcome changes by age. In reading this how-to article from UCLA's Institute for Digital Research & Education-...
0
votes
0answers
27 views

interpreting a log-log-linear model of two continous variables with or without interaction terms

I am regressing ecological distances between communities (as expressed as similarity) over their spatial and temporal distance on a regular grid of 360 sampling stations divided over six time points. ...
0
votes
0answers
17 views

PROCESS moderation - significant interaction, but non-significant effects at both values of the moderator

I'm testing the hypothesis that W moderates the effect of X on Y. The PROCESS output has indicated a significant X*W interaction under 'Test(s) of highest order unconditional interaction(s)' (p = ....
0
votes
0answers
21 views

Interaction between Ordinal and Dummy Variable?

Hello ladies and gentlemen, I am interested whether an existing effect is altered by the levels of another effect. As far as I know, including interaction variables is an appropriate way to explore ...
0
votes
1answer
27 views

Is it ok to use control variables in a moderator/interaction analysis in experimental design?

I have a question concerning the inclusion of control variables into my research. I have data from an experimental, randomly distributed social protection program. I want to test whether a moderating ...
1
vote
3answers
101 views

How to Illustrate Continuous-Continuous Interactions

What is the best way to illustrate an effect modification from a general linear model? I can use GraphPad Prism or R; can anyone point me resources showcasing how to produce publication ready plots ...
1
vote
1answer
36 views

Conducting a subgroup analysis with regression modeling

I'm conducting a survival analysis using Cox Proportional Hazards regression to identify prognostic factors for cancer patients. My covariates include information such as age, sex, tumor location etc. ...
2
votes
1answer
72 views

Heteroscedasticity consistent (HC) standard error analysis and interaction effects in an OLS

I have made a model with several variables, and 8 of them interact with a dummy to find interaction effects. These are added stepwise, resulting in three models. Now, through a Breusch-Pagan test I ...
0
votes
1answer
13 views

Will the main effect of two binary independent variables change when I enter them in a regression with their interaction term?

If I have two dummy independent variables (both binary, with two levels each) in a regression, then how do I construct the the interaction variable? By coding both variables as (1,0) and multiplying ...
0
votes
0answers
18 views

Interpret continuous x continuous interaction

I am trying to describe the interaction term you can see below in the image. I know that I can do a median split of the potential moderator in order to get the slopes per group. I am however also ...
0
votes
1answer
25 views

How to interpret categorical variable significant ANOVA interaction in R?

I have this output from a R ANOVA analysis and the graph attached. I want to verify if the interpretation for the scenario is correct? ...
1
vote
1answer
15 views

Bias in average treatment effect with least-squares when continous interaction terms

I hope someone can clarify this for me: When I am estimating treatment effects with a regression model, I can use interactions between the treatment indicator $W_i$ and covariates $X_i$ to model ...
0
votes
0answers
15 views

Evaluating the significance of individuals parts of a combined score using a linear regression

Background We are studying peoples inflammation in response to having a certain medical condition. We have a group ~300 of patients, of which about half of these have this condition. We have seen ...
0
votes
0answers
26 views

interpretation of AME for logistic regression with log transformed and mean centered variable with interaction

I transformed my independent variables: MCfunction <- function(x) (log(1+x) - mean(log(1+x), na.rm=T)) ...
0
votes
1answer
30 views

What are the best techniques for mediation analysis?

I am running a model of the following form: lm(outcome ~ treatment) in which I cluster standard errors at the participant level. I ask respondents at the end of ...
0
votes
0answers
30 views

Can you conduct contrast analyses when interaction effect is non-significant?

I ran a 2 (factor A: A1 vs. A2) X 2 (factor B: B1 vs. B2) between-subjects design experiment. I had an a priori prediction that the effect of factor B (i.e. the difference between B1 vs. B2) would ...
0
votes
0answers
8 views

Moderation and Ancova

I conducted a repeated measures anova with accent (British versus American) as 1 level and dress style (business, super casual, and business casual). My dv was how professional each was rated (1 to 7)....
0
votes
1answer
30 views

question about lm function in R

I have a simple question to ask regarding the lm function (and linear models in general). I am trying to predict y based on x, z, and a x*z interaction. If I simply predict y based on x I get the ...
1
vote
1answer
52 views

Baffled by inconsistency between 95% CI for OR and p-value

I am using logistic regression to model the effect of two production variables on the occurrence of tuberculosis. My independent variables are A (farm size: 0 for small, 1 for large) and B (cattle co-...
0
votes
0answers
17 views

Machine Learning Algorithm for Predictions Outside of Feature Space

I have a dataset with only a few features (about 5 or 6) that I am interested in using to make predictions related to an outcome, and the context in which I am making the predictions is outside of my ...
1
vote
0answers
23 views

R: Modelling estimates for the factors and 'sub-factors' of a predictor variable within a GLM

To take a simple example, let's say the model contains a dichotomous predictor variable with the factors {Group X, Group Y}, where all observations can be categorized into one of the two groups. ...
0
votes
0answers
20 views

Mediation and centering

I am running a mediation model with 2 interaction terms (gender x happiness and gender x hours spent working per week) and one dependent term (income). I am wondering if I should mean center these ...
0
votes
0answers
21 views

Calculating partial dependence function of many variables

In this answer How o calculate partial dependence when I have 4 predictors? there is a great example on how to calculate the partial dependence function for $X_s$ when $X_s$ accounts only for one ...
0
votes
1answer
82 views

Mean centering interaction terms

I want to mean center my interaction terms in a regression model (i.e., make the mean zero for each variable). I understand that I am supposed to mean center my variables first and then multiply them ...
0
votes
1answer
38 views

Creating interaction terms

I am relatively new to statistical analysis and so please forgive me for any cumbersome language/explanations. I'm interested in how sex and race interact to affect the experience of discrimination ...
3
votes
1answer
66 views

GAM factor smooth interaction--include main effect smooth?

I am working with a dataset it which I am interested in modeling an age*sex interaction in the GAMM framework. From examples I have seen and documentation I have read, this is typically accomplished ...
1
vote
0answers
46 views

Modelling interaction effects with interflex in STATA

I am trying to model interaction effects with the interflex STATA package from Hainmueller et al. (2019). This is supposed to provide graphics to better gauge the robustness of interaction effects in ...
0
votes
0answers
30 views

Is it possible to create simple slopes with quadratic variable?

Interactions are often explained by means of simples slopes. A simples slope is the effect of X1 on Y, at a specific value of X2. But what if the variable X1 is a non-linear? Is it possible to ...
0
votes
0answers
46 views

Modeling Pre-Trends in Difference-in-Differences

To get right to the point, the canonical difference-in-differences design is as follows: $$ y_{it} = \alpha + \gamma T_{i} + \lambda Post_{t} + \delta (T_{i} \times Post_{t}) + \varepsilon_{it}, $$ ...
1
vote
1answer
18 views

Comparing proportions of two samples in time

I am trying to compare if the proportion of one bird subspecies in a roosting area is different now from over 20 years ago. My dataset looks like following: -In 1996 birds were counted at a ...
0
votes
1answer
25 views

How to denote a simple slope coefficient (interaction)?

I'm using sslope in stata to test the linear relationship between x and y for different values of my moderator. The output of sslope provides me with a significance level and a coefficient. As far as ...
1
vote
0answers
27 views

BACI ANOVA with nesting in interaction

I'm doing a BACI (before-after-control-impact) analysis. The data structure is as follows: 2 sites (one control and one impact), 2 years before and 2 years after. Assuming that sampling years aren't ...
1
vote
0answers
30 views

Include main effect when specifying varying coefficient models with GAMM?

I am trying to model an interaction between two continuous variables in the GAMM framework using gamm in R. For simplicity's sake, I am ignoring the repeated ...
0
votes
0answers
27 views

Centering variables in multidimensional data

Assume you have a panel data set, that means for each car (CAR), with several individuals (IDs), the dependent variable is given as the power (POWER) created by an engine, over time (time). Further ...
1
vote
0answers
16 views

Inconsistent results between sjPlot and Anova()when including interaction terms in lmer() in R

I am using this R package "sjPlot" to plot the forest-plot of standardized beta values. My model includes interaction terms ...
2
votes
1answer
102 views

GLM Categorical IV Predictor vs Group by Analysis

I am modeling a continuous dependent variable with a couple of covariates (known a priori) and a variable of interest. I ran into an issue of interpretation which I'd like to clear up. When I ...
3
votes
1answer
32 views

Can I remove a dummy variable when it is not significant by itself, but its interaction with another variable is?

I have the following model based on the financial returns of a company as a dependent variable of a stock market index, and a dummy variable interacting with USD exchange rates to my currency. The ...
0
votes
0answers
9 views

Moderation Analysis with Ordinal Dependent Variable

My knowledge of statistics is unfortunately rather limited, at a basic undergraduate level. Part of my current project involves conducting a moderation analysis between one independent, one moderator, ...
2
votes
2answers
82 views

Why is the interaction term defined by multiplying the IVs? [duplicate]

I am trying to get a deeper mathematical understanding of regression, beyond just applying it and interpreting the output. Can somebody provide me with the mathematical rationale for why interaction ...
0
votes
1answer
45 views

interpretations of regression results with interaction effects when continuous variable involved

I did a general linear model with two independent variables (math (a continuous variable) and group (a categorical variable with 2 categories)) in SPSS. I have included the interaction effects of ...
0
votes
0answers
50 views

LRT p-values for main terms in non-additive models

Likelihood Ratio Test (LRT) performs better than Wald test to get p-values of a model’s predictors. Using R, it is pretty common that you report the intercept and slopes estimates from the summary() ...
0
votes
0answers
16 views

Using PROCESS and Johnson-Neyman to identify points at which a moderator becomes significant within specified categories

I've recently been using Andrew Hayes' PROCESS macro for SPSS to probe an interaction I've found in my dataset. Originally, I was planning on conducting a spotlight analysis comparing high and low ...
1
vote
0answers
25 views

Confused about motivation for variable selection - probit model

I am running a probit regression which aims to determine which variables influence whether a graduate feels 'mismatched' (e.g. not using the qualification they've learned) in their job. We are using ...
1
vote
1answer
54 views

Interaction not significant in Cox regression model?

I ran a cox model with an interaction between two categorical variables (sex and treatment group) included like: ...
0
votes
0answers
25 views

Interpret interaction terms in Poisson

I'm using GLM to represent a Poisson model with the log link function. The response variable is a count variable representing the number of deaths. Both temperature and season are explanatory ...
1
vote
1answer
105 views

interactions involving two continuous predictors with emtrends

Let's say I have a model with two continuous predictors (nitrogen and temperature) and one categorical variable (variety). <...
0
votes
1answer
22 views

PROCESS macro or SEM for mediation model with latent variables

I am conducting a survey to analyze the effect of a binary variable X on a latent variable Y. The effect is assumed to be mediated by another latent variable M. Moreover, the effect of X on M is ...
-1
votes
1answer
34 views

Dummy as moderator in regression analysis

I am working on data about the food industry, where companies should be divided according to their region (Asia, Europe, and North America) via dummies. This is supposed to be the moderator variable. ...