Questions tagged [heterogeneity]
Use this tag for questions in the context of meta-analysis; use [heteroscedasticity] in the context of regression modeling. Heterogeneity arises when the primary studies are not drawn from a single population.
72
questions
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0answers
77 views
correlation with diverse characteristics
What does it mean to say "incidental parameter bias due to correlation between past realizations of the data and the unobserved heterogeneity (diverse characteristics)"? How can there be a correlation ...
2
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0answers
21 views
Difference in Difference heterogeneous treatment effect based on scale of pre-post difference
In a Triple Difference model can we introduce a dummy variable based on scale of difference of dependent variable between pre and post periods? Example: divide both treatment and control groups into 2 ...
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0answers
21 views
One-way ANOVA method validation
Here is my case:
Let's say we have 50 polygons(looks like this:and a point set distributed within these 50 polygons. So that for each polygon, there is an associated point density. What I want to ...
1
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0answers
8 views
Moderator variable in meta-regression analysis and treatment effect heterogeneity
Meta-regression may reveal that variable A explains heterogeneity in pooled treatment effect of X.
In a clinical trial I can investigate whether there is interaction between treatment allocation and ...
3
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0answers
30 views
Applying Heterogeneous treatment effects to clinical research (non technical explanation)
I'm trying to understand the hype around this estimation of heterogeneous treatment effects in the machine learning literature lately. It seems super interesting, but alot of it is beyond me. I read ...
0
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0answers
42 views
Using multinomial logistic regression to test for heterogeneity
I have been asked to use polychotomous logistic regression to test for heterogeneity or independent variable across multiple outcomes levels, and then change-in-estimate method to identify other ...
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0answers
46 views
Looking for R package or function to quantify heterogeneity/homogeneity of groups of character strings [closed]
I’m looking for an R package or function that I can use to measure the relative homogeneity/heterogeneity of groups of character strings. There are about 50 groups, each with thousands of character ...
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0answers
35 views
Calculation of I-squared in meta-analysis of diagnostic accuracy
I would like to calculate heterogeneity statistics (Cochran's Q, I-squared) for a meta-analysis of diagnostic accuracy. I successfully used the 'mada' package in R to calculate these statistics, but ...
0
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0answers
13 views
Heterogeneity in pooled cross sectional data
Hey I'm trying to estimate the effect of minimum wage changes on unemployment using data from the American Community Survey.
Since the ACS is pooled cross sectional data, the sample which is ...
2
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1answer
77 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. ...
1
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0answers
37 views
Why is Metafor R package giving an I2 for fixed effects meta-analysis model (rma.uni)? [closed]
I'm trying to run a fixed effects meta-analysis using the Metafor R package and in the documentation I read that it does not return an I^2 for fixed effects models, only for random effects models. ...
2
votes
2answers
164 views
Are there good alternatives to Cochran's Q test for heterogeneity in meta-analysis?
We used the Q test to determine heterogeneity with p-values <0.10. A highly recognised statistician commented that the Q test has low power and that it should not be used to determine presence of ...
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0answers
29 views
test for homogeneity and heterogeneity in clustering
I want to check if there is a way (or test) to verify homogeneity among and heterogeneity between clusters, besides the almost 30 clustering indices that are available (see NbClust). I am also aware ...
2
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1answer
30 views
Re: Random Effect Model in Binomial Proportions Meta-analysis
I have used a random effects model for the meta-analysis of binomial proportions and have encountered several queries.
In one meta-analysis, I have four studies.
Sample size of 98, 58, 107, 62
...
2
votes
0answers
30 views
Homogeneity test in survival meta-analysis with adjusted HR
I was wondering what was the way to measure heterogeneity in a survival meta-analysis.
I have for each study, an hazard ratio calculated with a penalized cox model (...
0
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0answers
21 views
How to compare two cox regression coefficient for one predictor on two different outcomes?
Here are the results of the univariate analyses by Cox regression to determine whether a variable has a differential effect on survival in the first 5 years versus the latter 5 years. But I don’t know ...
0
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0answers
35 views
Treatment effect (DID) heterogeneity conditional on a continous variable
as stated in the title, I'm thinking about exploring the heterogeneity of treatment effect result from a DID design based on a continuous variable. To be specific:
\begin{align}
& \mathrm{Profit}...
1
vote
1answer
77 views
Heterogeneity test in meta-analysis
In a random effect meta-analysis model with one categorical independent variable $\theta_{ij}=\theta_i+s_j+\epsilon_j$, where $\theta_{ij}$ is the observed effect size in category $i$ in study $j$, $\...
2
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3answers
60 views
Is it worth doing (single-armed) meta analysis if the studies' heterogeneity is very large?
I'm currently trying to perform a single-armed meta analysis of immunotherapy on breast cancer, which I believe this meta analysis will be the first among its intervention and cancer subtype.
The ...
2
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0answers
24 views
What heterogeneity test is appropriate for my study? And, what is the use of correlation between median PFS and median OS [duplicate]
I want to perform a meta analysis of a particular subjects of cancer. My effect sizes are Overall Response Rate (ORR), Disease Control Rate (DCR), Duration of Response (DOR), Progression-Free Survival ...
0
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1answer
97 views
How to correct standard errors for heterogeneity and intra-group correlation?
I got my article manuscript back from review and one notion from a reviewer was that in my analyses "[s]tandard errors are not corrected for heterogeneity or intra-group correlation", s/he apparently ...
0
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0answers
28 views
I squared for measuring homogeneity
I can't seem to find a simple resource that explains what I can use the I2 (derived from Cochrane's Q), often used in meta-analyses for, exactly. Most, if not all resources I find on the subject go on ...
1
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1answer
32 views
In meta-analysis Q-statistic, is there a better way to compute the degrees of freedom?
I am working with a meta-analysis, and attempting to quantify heterogeneity across several data sources. I am using the following formula:
$Q = \sum_i(w_i \cdot (y_i - \mu_F)^2)$
where $y_i$ is the ...
1
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0answers
146 views
Fixed or random effects in a subgroup analysis where heterogeneity is present in one of the subgroups but not the overall pooled result?
I am looking at a meta-analysis where a subgroup analysis has been performed, as it is important to consider the treatment effect within 2 subgroups of interest, as well as the overall pooled result.
...
1
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0answers
34 views
Deriving heterogeneity measures for each level in a multi-level moderator meta-analysis
I'm running a multi-level moderator meta-analysis using the R package metafor. To derive $I^2$ for the metafor analysis as a whole, which doesn't come out ...
3
votes
3answers
318 views
Calculating Standard Error of Tau - Meta Analysis
I am conducting a meta analysis using the metafor package in R and am trying to calculate the Standard Error (if possible) of the Tau statistic.
The S.E of the tau-...
1
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0answers
143 views
Using metafor with multiple outcomes from single studies, and how to calculate within- and between-study heterogeneity?
I am currently conducting a meta-analysis where we have several studies that report multiple outcomes from the same participants. We've been advised to use the ...
2
votes
2answers
289 views
How to interpret heterogeneity in a meta analytic model
I try to fit a random effects model for my thesis, a meta analysis of studies about team planning and team performance.
I'm using R and the package metafor to create z correlations and variance (yi, ...
2
votes
1answer
397 views
Computation of Network Homophily / Heterogeneity
I am quite confused about the calculation of network homophily in network analysis. Right now I am computing the homophily using the following function, which has been written and also described by ...
2
votes
1answer
70 views
proportional meta-analysis, small confidence intervals and I square of 100 %?
I am performing a meta-analysis of proportions, I have data about the number of cases and the total sample sizes.
I will be using the Freeman-Tukey double arcsine (Freeman & Tukey, 1950; Miller, ...
1
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1answer
56 views
Meta analysis: is there such a thing as too little heterogeneity?
First time I've seen results like these and they make me feel uneasy. Is it even appropriate to do a meta-analysis here? Even my poor forest and funnel plots are messed up.
...
0
votes
1answer
330 views
Panel regression with multiple fixed effects and heterogeneity
For a research project I am supposed to estimate a panel regression model on a dataset with user data over observation time (the sample is assumed to represent general population). The supervisor is ...
1
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1answer
258 views
Testing for treatment effect hetereogeneity in regression discontinuity design
I am not a statistician or econometrician, so please bear with me. For a term paper, I am estimating local treatment effects using a regression discontinuity design, and I want to test whether the ...
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0answers
1k views
Heckman selection model for unbalanced panel data
I want to apply a heckman sample selection model (implemented for example in the R package sampleSelection, see here). However I have an unbalanced panel with ...
3
votes
1answer
493 views
How do I calculate confidence intervals for I-squared in order to assess heterogeneity between two pooled studies?
I am conducting a meta analysis and for some of my pooled data, there are only two studies available. Based on this publication I have been calculating confidence intervals around I-squared in order ...
3
votes
2answers
201 views
I-Squared: From Calculation to Concept
In meta-analyses, it's common to report the I-Squared statistic as a measure of heterogeneity of results across studies. The definition given by Higgens 2003 as "the percentage of total variation ...
1
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1answer
42 views
Regression: OLS: residual split
A friend of mine is estimating the following model, using ols:
$y=\alpha + \beta X + u$,
where $y$ and $X$ are continious variables, $\alpha$ and $\beta$ are parameters and $u$ is an error ...
2
votes
1answer
155 views
Intuition on simple linear regression signal plus noise model
I'm currently studying linear regression on this book
"F.M. Dekking - A Modern Introduction to Probability and Statistics: Understanding Why and How" where the signal+noise model is presented:
$Y_i =...
3
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0answers
62 views
Framework for simulating SEM data w/ moderation + mediation, testing models
I'm interested in extrapolating treatment effects from RCTs to new populations under conditions where populations exhibit relevant differences that induce differences in treatment effects.
My aim is ...
1
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1answer
455 views
How to analyse unbalanced panel data with attrition and defiers?
I'm working with a panel data from a quasi-experimental study with the following characteristics
1) Unbalanced covariates between the control and the treatment group (according to Hotelling's T-...
4
votes
1answer
583 views
Two Study Meta-Analysis: Fixed- vs. Random-effects and heterogeneity
I browsed through several papers and discussion but I am still not sure what is correct.
I conducted two studies on the same topic using similar methods and the same design (independent t-tests). ...
3
votes
1answer
232 views
Clarification of LLNs when non i.i.d. observations
I have a question on how to interpret Law of Large Numbers. Its meaning seems to me clear when we are in the i.i.d. case:
Consider $(Y_i)_{i=1}^n$ i.i.d. random variables with $\mu\equiv E(Y_1)<\...
2
votes
1answer
322 views
Heterogeneous treatment effects with 2SLS local average treatment effect (LATE)
I am interested in a strategy to calculate heterogeneous treatment effects with an IV strategy for local average treatment effects (LATE).
I am estimating the effect of postsecondary educational ...
5
votes
1answer
20k views
Difference between one-way and two-way fixed effects, and their estimation
Consider a basic linear unobserved effect panel data model, e.g.:
$$Y_{it}=\beta x'_{it}+c_i+\lambda_t+u_{it}, \quad t=1,\dots,T$$
where the vector $x_{it}$ contains the independent variables and $u_{...
2
votes
1answer
177 views
How to deal with unexpected low heterogeneity in meta-analysis?
I am performing a meta-analysis in R with metafor package. Primary studies report the reduction of plant species to certain amount of nitrogen fertilization. Effect ...
3
votes
1answer
368 views
Meta-analysis: significant heterogeneity vs. significant between-study variance
I am running a simple random-effects meta-analysis in R using the metafor package, with random intercepts at the study level:
...
1
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0answers
27 views
Quantifying group homogeneity
I'm trying to find a way to quantify the homogeneity of a group.
An example dataset is below, where group D, for example, has 5 members of type1, 1 member of type2, and 1 member of type3. Groups A ...
1
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1answer
266 views
influence of number of observations on entropy calculation
I am performing a genomic study where I am interested in determining the heterogeneity of epigenetic alleles (DNA methylation patterns) in specific genomic locations. Previous work on this subject has ...
5
votes
1answer
565 views
Simulation of random-effects meta-analysis yields biased tau^2
I need to realistically simulate study effect sizes and within-study variances for a random-effects meta-analysis in which the outcome is a relative risk. My question: why does this simulation lead to ...
1
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0answers
426 views
Heterogeneity testing in logistic regression models
We ran 5 separate logistic regression models testing a set of independent variables on 5 different country-specific datasets. Our goal was to assess the relative contributions of known risk factors of ...
