A treatment effect is the causal effect of some "treatment" or policy intervention on an outcome variable. Such effects can be estimated with data from randomized or quasi experiments, and clinical trials or with observational data and methods for causal inference.

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How to set sum contrasts for unbalanced factors

Let's say that I have a model where the response time depends on accuracy (0/1, coded either as categorical or numerical) and another categorical variable (pres: idem/diff), both interacting with the ...
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20 views

Control group construction in Synthetic Control Method

I want to use the Synthetic Control Method to estimate the effect of the adaption of a new ballot institution (treatment) on fiscal policy. My sample consists of 20 units observed at 100 time points. ...
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20 views

Difference in difference with pre and post period

I wanted some guidance on some test I am performing. Basically I want to see the difference between the effect of unionisation on 13 countries grouped into 3 that don't have unions and 10 that have ...
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6 views

Sampling with Replacement and Excessively Sampling a Few Observations

If I am trying to construct a matched control sample and I am sampling with replacement, there is the possibility that I may select the same observation many many times. What bias could this induce as ...
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5 views

Estimate if effect sizes in a multi level model differ

I have the following model summary: ...
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3 views

Thresholds as function of treatment

Y=function of some treatment. So when a treatment is applied I want to develop thresholds(depending on some sort of variance). Any ideas?
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7 views

What test to use

I have a group of athletes that performed 2 trials pre and post a treatment ( 2 control and 2 post-treatment trials). The trials were performed pre/post and after 7 minutes pre and post again. I ...
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1answer
19 views

Compare effect of resection extent on survival in two types of tumors

I have two groups of patients with similar, but different brain tumors (tumor type 1 and 2 for simplicity). All underwent surgery, the achieved extent of resection over a certain cutoff value should ...
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0answers
23 views

Best method of analysis for 2 independent groups for multiple tasks before and after treatment?

I have two independent groups at the start of the study. Both groups went through the same study procedure where they went through multiple tasks (not necessarily repeated measures). They were then ...
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2answers
55 views

Modelling effect of advertisement on sales with ARMAX

I am trying to model the effect of advertisement on sales in Stata. The data is weekly and there are around 150 observations. I started by applying an ARMAX(1,0,1) model with the following exogenous ...
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13 views

Repeated measures binomial effect confidence intervals

I have a repeated measures study design with two separate conditions in a memory task where one must recognize previously seen items in a list. The conditions are concrete vs. abstract. I'd like to ...
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0answers
28 views

Possible to estimate average treatment effect (ATE) using generalized estimating equations (GEE)

I know that the method of generalized estimating equations (GEE) returns "population-averaged" coefficients, but for nonlinear link functions is it possible to use GEE to estimate the average effect ...
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35 views

Inverse probability weighting and regression adjustment

I am trying to estimate causal effects, the model is: $Y_i = \beta_0 + \beta_{1,i}T + \gamma x + u$ And where the treatment indicatior is: $T = I(\lambda x + d > 0)$ Where $x$ is a dummy. The ...
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57 views

Competing risks using crr in R with time-dependent dummy variable indicating treatment

I am trying to incorporate a time-dependent dummy variable for treatment using crr in the cmprsk package in ...
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0answers
15 views

Test treatment effect in two or more populations

I have some data to analyze and am struggling finding out the right test to use. My problem is fairly simple: I want to compare the effect of a treatment in two (or more) populations. H0: Treatment ...
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0answers
23 views

effect on time series

I have financial ratios for 13 companies for three years. In the second year all the companies issued a bond. I want to measure the effect of issuing the bond on the financial ratio results of each ...
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30 views

Substantive interpretation of main and interaction effects in nested hierarchical linear models using effect coding

I have two categorical IVs each with three levels: group (Control, Int1, Int2) and a longitudinal variable wave (T1, T2, T3). ...
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1answer
64 views

Unconfoundedness in Rubin's Causal Model- Layman's explanation

When implementing Rubin's causal model, one of the (untestable) assumptions that we need is unconfoundedness, which means $$(Y(0),Y(1))\perp T|X$$ Where the LHS are the counterfactuals, the T is the ...
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1answer
54 views

Non-random assignment to treatment group due to anticipation of treatment in difference-in-differences design

I have a very basic question regarding a DiD-Design. If the subjects in this design select themselves into treatment/non-treatment group because they anticipate the treatment (e.g., they want to ...
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0answers
13 views

Natural Treatments- Time Varying Effect

I am studying for my Econometrics exam and I have come across this question which I am kind of struggling with. This question is concerned with the housing pricing in one of the suburbs in Sydney ...
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0answers
55 views

Interpretation of ATE for IPTW propensity score analysis

I understand how we interpret the average treatment effect (ATE) when we use propensity score matching. We match on propensity score, and then subtract away the groups to get the average treatment ...
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0answers
21 views

Measure of an individual's contribution to a coefficient in a panel regression?

I'm not very good at statistics, so this is probably an easy and perhaps definitional question. I have a panel setup with an outcome variable $Y_{it}$ and a "treatment" variable $X_{it}$ which ...
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0answers
25 views

Treatment Effect Approach and Selection Bias

Suppose to have the National Health Interview Survey data (NHIS), the health status of the observed people as outcome $y_i$, which has got different potential outcomes on the basis of a treatment ...
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21 views

Does contrast.treatment Wald test inflate type I error rate?

I have an experimental protocol with 3 groups of rats. First group is on standard diet and the other two were given ipersaline diet. ...
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49 views

Confidence of Effect Size Differences

Hedges and Olkin (1985) suggest the following procedure for computing confidence intervals for Hedges' g resp. d $$ \text{CI} = g \pm 1.96 \sqrt{(n_2+n_1)\big/(n_2n_1) + g^2 \times .5\big/(n_1+n_2)} ...
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1answer
44 views

Specification of longitudinal mixed-effects model with varying treatment times, varying observation times in lme4

I am familiar with fixed-effects linear regression models, and have done reading on mixed-effects models. I am attempting to fit a model based on observational data, where treatments come at varying ...
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126 views

Exact Matching and Diff-in-Diff design using panel data with time-varying treatment

I want to combine matching with a Difference in Difference strategy to assess whether a forced move has been beneficial to relocatees (increased income, more affluent neighbourhood) compared to their ...
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1answer
31 views

Experimental treatments assigned via email how best estimate average treatment effects?

A growing number of social experiments are conducted outside of the laboratory, and by assigning the treatment condition through emails (e.g., often the content of the email is the intervention ...
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1answer
43 views

Experimental Design: Number of treatments and replications

I am learning about experimental design. I have been provided the following definitions: Factors: Variable(s) manipulated by researchers in order to observe response(s) Levels: Values of factors ...
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148 views

Causal Trees to Estimate Heterogenous Treatment Effects: Transformed Outcomes [Machine Learning in Python]

I am interested in using off-the-shelf tools like scikit-learn for Python to implement the Athey-Imbens recommendation for estimating treatment effect ...
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0answers
19 views

Compute Local Average Treatment Effect from Tobit-5 Selection Model in sampleSelection package

I am trying to use the tobit-5 model in the sampleSelection package in R. This models the selection of a treatment effect, then the outcome of interest when the treatment is assigned and when the ...
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1answer
47 views

How can I assess the efficacy of this treatment?

I have ~650 scores on various measures of academic performance in a subject. One novel aspect of the subject was that a study website was conducted on which students could answer practice questions. ...
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0answers
14 views

Standardized test data with a treatment group and demographic traits

I am looking for the most appropriate procedure to identify treatment groups that performed better than nontreated groups on a standardized test score. Sample variables are: Treatment (Yes or No) ...
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3answers
252 views

Standard error clustering under treatment assignment in groups of varying size

Basic setup: Unit of observation is the individual. Treatment (binary) is assigned on city level. Every state contains 4 cities, 2 get randomly chosen for treatment, 2 control. There are only few ...
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28 views

Two years of data with pre/post, need to figure out size of impact

I have 2 data sets: 2013-14 and 2014-15. Each year has pre and post data, measuring literacy. Sample size is 101 in one year and 93 in the other. I would like to determine if 2014-15 results were ...
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21 views

Measuring training effectiveness

I am measuring training effectiveness using a control and experiment group design. However, as it is a live project in an organization having an 'interest based' approach for training subscriptions, I ...
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306 views

How to estimate Carry-over effects in 2x2 Crossover study using R?

I am struggling to understand how to estimate the carry-over effect in a 2x2 Crossover experiment using R, there are several examples using SAS but (1) I don't understand the syntax and (2) I would ...
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2answers
97 views

Propensity Score Matching

What is the right approach when there is a variable that does not affect participation but effects the outcome measure? I have data set of the health outcome of a treatment and control group. I have ...
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0answers
15 views

Experimental Design Optimal allocation to treatment

I have trying to design an pre-post study on the effectiveness of a particular media platform in inducing behavior change. The 700 households are distributed in 6 geographical clusters. They have ...
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2answers
271 views

Comparing the Fold Change (Effect size) after a treatment

I have been using this site for the past year to get tips on stats but I have run into a problem that I cannot overcome. It isn't too complicated, but I am not sure how to determine significance or if ...
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0answers
17 views

Methods to deal with latent variables

I had a general question about methods to adjust for the effect of latent variables (specially variables that are suspected to be confounder) in observational studies. In particular, I'm working on a ...
5
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1answer
501 views

What is the best way to visualize difference-in-differences (multi-period) regression?

What's the best way to visualize difference-in-differences for both binary and continuous treatment? Do I regress the outcome variable on the set of controls but exclude the treatment variable and ...
2
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1answer
3k views

How do I interpret a “difference-in-differences” model with continuous treatment?

How do I interpret the ATE coefficient (i.e., the post-treatment indicator interacted with the continuous variable)? Does it make sense? Should I break it down into subgroups and just run a fixed ...
0
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0answers
58 views

In two places at once: treatment and control groups

When performing a treatment study (e.g. a difference-in-differences design) in multi-dimensional panel data (e.g., firm-individual-time, bank-firm-time, etc.) is it ok if the "smaller" cross-sectional ...
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27 views

Large standard errors in IV regression [duplicate]

I am encountering very large standard errors of the endogenous regressor (bigger than the size of the coefficient) in the second step of my treatment-effects model (...
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0answers
564 views

propensity score matching and difference in difference

I am trying to analyse the impact of a cash stipend program, onto child learning outcomes. I have first modeled the conditional probability of each student receiving this program. So basically I have ...
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1answer
87 views

Not understanding reason for demeaning covariates in program evaluation regression

I am reading the Imbens et al. 2009 paper on program evaluation methods: http://dash.harvard.edu/bitstream/handle/1/3043416/imbens_recent.pdf?sequence=2 On page 24, discussing simple regression ...
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0answers
60 views

Regression analysis for a clinical trial with repeated measures

I am currently working with a dataset that was collected from a depression study at baseline and 6 months for a group of 60 participants. Also these participants are divided into 4 groups based on ...
2
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1answer
64 views

Exploring effect of treatment on count data

I've collected data on animal visitation at four different points in time. The four time points represent the total animal visitations over a three day period, i.e. 3 days of monitoring at four ...
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1answer
127 views

Check if density plots are significantly different (with R) [closed]

I have daily data on cars per minute passing certain points. The data covers weekdays of 4 months, July and August, for 2013 and 2014. In August 2014 a toll (treatment) was introduced. I would like to ...