Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Bridging observational studies and randomized experiments by embedding
  the former in the latter   The health effects of environmental exposures have been studied for decades,
typically using standard regression models to assess exposure-outcome
associations found in observational non-experimental data. We propose and
illustrate a different approach to examine causal effects of environmental
exposures on health outcomes from observational data. Our strategy attempts to
structure the observational data to approximate data from a hypothetical, but
realistic, randomized experiment. This approach, based on insights from
classical experimental design, involves four stages, and relies on modern
computing to implement the effort in two of the four stages.More specifically,
our strategy involves: 1) a conceptual stage that involves the precise
formulation of the causal question in terms of a hypothetical randomized
experiment where the exposure is assigned to units; 2) a design stage that
attempts to reconstruct (or approximate) a randomized experiment before any
outcome data are observed, 3) a statistical analysis comparing the outcomes of
interest in the exposed and non-exposed units of the hypothetical randomized
experiment, and 4) a summary stage providing conclusions about statistical
evidence for the sizes of possible causal effects of the exposure on outcomes.
We illustrate our approach using an example examining the effect of parental
smoking on children's lung function collected in families living in East Boston
in the 1970's. To complement the traditional purely model-based approaches, our
strategy, which includes outcome free matched-sampling, provides workable tools
to quantify possible detrimental exposure effects on human health outcomes
especially because it also includes transparent diagnostics to assess the
assumptions of the four-stage statistical approach being applied.

5
The categories of this paper are: gr-qc
12
The categories of this paper are: nucl-th
3
The categories of this paper are: physics
7
The categories of this paper are: hep-th
11
The categories of this paper are: hep-lat
23
The categories of this paper are: solv-int
30
The categories of this paper are: q-alg
0
The categories of this paper are: hep-ph
32
The categories of this paper are: atom-ph
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The categories of this paper are: astro-ph
10
The categories of this paper are: q-bio
22
The categories of this paper are: chao-dyn
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The categories of this paper are: supr-con
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The categories of this paper are: cond-mat
15
The categories of this paper are: nucl-ex
2
The categories of this paper are: math