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.

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21 views

Meta Analysis - Find the pooled Odds Ratio, given each subjects OR, Lower and Upper Limit and Z-test values

I have a problem I have been working on but can't seem to understand how to go about solving, and any help would be most appreciated. My Problem: I have been asked to find the pooled OR and it's 95% ...
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9 views

Can I test whether there is a group of observations in a dataset having a treatment effect in the opposite direction with respect to the ATE?

Suppose that I'm looking for the effect of a shock (for example, a natural disaster, or the current Covid pandemic) on given outcomes, where each observation corresponds to a different person. I ...
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12 views

How to check for heterogeneity over time and location for rate data

I have data that consists of different locations, with repeated observations over time, of counts (and a denominator to make a rate). eg ...
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1answer
19 views

DiD with time invariant and time variant treatment?

I am currently working on a project that seeks to study the impact of the subprime crisis on family firms and non-family firms. In this, I have imagined to use a DiD estimator to account for ...
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2answers
50 views

Heterogeneous Treatment Effects with Continuous Treatment (e.g. using BART)

Overview: Most of the causal inference literature (both theoretical and applied), I have seen on heterogeneous treatment effects, only considers the case with a binary treatment $T\in\{0,1\}$. However,...
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2answers
18 views

Group Heterogeneity in a Meta-Analysis - Layman's Terms

EDIT: I now believe this question was based on misguided information. See my answer. I'm looking through this meta-analysis (of studies on the effects of mindfulness on healthy individuals) for some ...
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43 views

Transforming Heterogeneous Treatment Effect Models (in EconML) into Average Treatment Effect Model (from DoWhy)

This question relates to the steps one would need to take in order to reproduce an answer from the DoWhy tutorial, using the EconML library code for heterogeneous causal effects. In DoWhy, there is ...
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1answer
80 views

Causal inference for multiple treatments with an observed set of properties

Note: I have rewritten this question quite a lot, because pzivich's answer made me realize that I had not formulated it accurately enough . In order to give the original context of pzivich's answer, I ...
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1answer
80 views

How to interpret Cox Model with time-varying coefficients

I fitted a Cox PH Model and upon examination of the Schoenfeld residuals it became apparent that the proportionality assumption was violated by several variables. Following Box-Steffensmeier & ...
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1answer
19 views

How to decide if frailty term needed

I´d like to ask the following question: Is there any sound procedure to test event-history/survival data for unobserved heterogeneity or any indicator that shows that a frailty term should be included?...
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1answer
79 views

OLS when $\beta_i$ varies across observations

Suppose that the data generating process is given by $$ y_i=\beta_i x_i+\varepsilon_i $$ where $\varepsilon_i\sim \text{iid }\mathcal{N}\left(0,\sigma^2\right)$. Note that the $\beta_i$ coefficients ...
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1answer
32 views

Calculating Effect Size from Wilcoxon W value (how to get the z value)

Im carrying out a meta-analysis where I have had to carry out my own wilcoxon test on the data. I am now calculating the independant effect sizes for each study to manually input to my excel ...
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9 views

Finite mixture model, nonlinear, parametric, individuals

Suppose that I think individual $i$ chooses number $c$ according to the formula $c = v(f(\delta, \gamma) x - \alpha y))$ where $v$ and $f$ are nonlinear functions. I know what form $v$ and $f$ take. I ...
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15 views

Hartung-Knapp-Sidik-Jonkman variance correction in meta-analysis

I am doing a meta-analysis of continuous data (SMD), number of studies (k) around 75, heterogeneity high (Tau-squared around 0.15, I-sqr over 75%). Our interest is in fact in a key subgroup analysis (...
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26 views

Equivalence between interaction and second difference measures of heterogeneity

I am trying to understand a paper used by Frank Harrell in his biostats course to demonstrate how NOT to present results from an analysis of heterogeneity of treatment effects (HTE). Frank's point is ...
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2answers
58 views

Meta-analysis: How to interpret a non-significant Q statistic but high I squared

I'm reviewing some meta-analyses on psychotherapies and trying to make sense of the statistics related to heterogeneity, specifically Cochran's Q and the I-squared value. I'm confused about how to ...
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22 views

LOOKING FOR THE OPTIMAL MODEL WITH GAMM

I conducted an experiment where earthworms were subjected to two treatments, with and without herbicide in the soil. Biomass measurements were taken every 12 days for 398 days and the biomass growth ...
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180 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 ...
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75 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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59 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 test ...
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11 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 ...
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33 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 ...
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0answers
72 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
73 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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111 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 ...
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1answer
192 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. ...
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68 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. ...
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2answers
280 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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1answer
53 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 ...
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0answers
44 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 (...
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1answer
87 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 $j$, $\...
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3answers
95 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 ...
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0answers
26 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 ...
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1answer
140 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 ...
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42 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 ...
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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 ...
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0answers
221 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. ...
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0answers
35 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 ...
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3answers
525 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-...
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0answers
275 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 ...
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2answers
362 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, ...
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1answer
669 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 ...
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1answer
78 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, ...
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1answer
62 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. ...
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1answer
705 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 ...
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1answer
333 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 ...
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1answer
719 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 ...
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2answers
431 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 ...
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1answer
48 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 ...