Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Defining and Estimating Effects in Cluster Randomized Trials: A Methods
  Comparison   Across research disciplines, cluster randomized trials (CRTs) are commonly
implemented to evaluate interventions delivered to groups of participants, such
as communities and clinics. Despite advances in the design and analysis of
CRTs, several challenges remain. First, there are many possible ways to specify
the intervention effect (e.g., at the individual-level or at the
cluster-level). Second, the theoretical and practical performance of common
methods for CRT analysis remain poorly understood. Here, we use causal models
to formally define an array of causal effects as summary measures of
counterfactual outcomes. Next, we provide a comprehensive overview of
well-known CRT estimators, including the t-test and generalized estimating
equations (GEE), as well as less known methods, including augmented-GEE and
targeted maximum likelihood estimation (TMLE). In finite sample simulations, we
illustrate the performance of these estimators and the importance of effect
specification, especially when cluster size varies. Finally, our application to
data from the Preterm Birth Initiative (PTBi) study demonstrates the real-world
importance of selecting an analytic approach corresponding to the research
question. Given its flexibility to estimate a variety of effects and ability to
adaptively adjust for covariates for precision gains while maintaining Type-I
error control, we conclude TMLE is a promising tool for CRT analysis.

30
The categories of this paper are: q-alg
33
The categories of this paper are: plasm-ph
8
The categories of this paper are: hep-ex
29
The categories of this paper are: funct-an
14
The categories of this paper are: math-ph
32
The categories of this paper are: atom-ph
18
The categories of this paper are: econ
6
The categories of this paper are: astro-ph
15
The categories of this paper are: nucl-ex
19
The categories of this paper are: eess
1
The categories of this paper are: cs
20
The categories of this paper are: acc-phys
17
The categories of this paper are: q-fin
11
The categories of this paper are: hep-lat
28
The categories of this paper are: alg-geom
5
The categories of this paper are: gr-qc