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.
85
questions
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1answer
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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0answers
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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0answers
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
...
1
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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 ...
7
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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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0answers
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 ...
3
votes
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 ...
1
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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 & ...
0
votes
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?...
1
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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 ...
1
vote
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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0answers
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 ...
1
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0answers
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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0answers
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 ...
2
votes
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 ...
1
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0answers
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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0answers
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 ...
2
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0answers
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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0answers
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 ...
1
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0answers
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 ...
3
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0answers
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 ...
0
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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 ...
1
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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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0answers
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 ...
2
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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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0answers
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. ...
2
votes
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 ...
2
votes
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
...
2
votes
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 (...
1
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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 $j$, $\...
2
votes
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 ...
2
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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 ...
0
votes
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 ...
0
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0answers
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 ...
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
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 ...
3
votes
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 ...
2
votes
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, ...
3
votes
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 ...
2
votes
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, ...
1
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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.
...
1
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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 ...
1
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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 ...
3
votes
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 ...
3
votes
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 ...
1
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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 ...
