Questions tagged [treatment]
The treatment tag has no usage guidance.
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Comparing treatment effects across groups
I created two donation campaigns, one loss framed (N:1993) and one gained framed (N:1989) I understood donations are usually veeeery low and the sample was a lot smaller than previously expected, so ...
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Can I Calculate a Local Average Treatment Effect (LATE) With Three Treatment Groups?
This is a conceptual question About Local Average Treatment Effects (LATE).
Basically, I ran an experiment that included three treatment groups and a control group. We measured our outcome variable at ...
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Comparing standardised values of microbial colony perimeters
I’m having a statistical problem (a rather major one) and I was wondering if you could help. I’m researching microbial chemotaxis and analysing colony perimeters by scanning their fluorescence. ...
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How to compare control group to treatment groups and also compare treatment groups to each other? Binary Data only
In my survey participants randomly got assigned to one of the four groups and had to choose between two options for three fictional purchases.
The treatment groups contain the same intervention but ...
user376199
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Difference in Difference Model for Tariffs
I am looking at exports of products that have been affected by tariffs with the control group as none tariff targeted products and the treatment group as tariff targeted products. How do I specify a ...
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Am I interpretting this interaction term correctly?
I am running a model with an interaction term and I am unsure of the interpretation even after reading the other questions here in the forum.
My model looks as follows:
Where roi is the return on ...
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How to treat a subject's possible preference
I have some animal preference data and would like some advice on treating it correctly. There are 10 subjects, and two trials dealing with a barrier product. The subjects were allowed to select one of ...
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Time Varying Difference in Differences Model
If I am looking at the impact of different tariffs in different months on exports,
can anyone tell me if this would be the correct difference in differences model?
Or would it be
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Treatment: Mean AND variance should be optimized. What test to use/how to use (for instance t-test)?
Assume a research on the effect of applying a treatment to improve health by normalizing level of some vitamins in the bodies of some people. We measure initially the level of the vitamin of sick ...
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Take multiple stratified samples from
I am interested in taking three separate stratified samples from a population so that I can assign them to different treatments. I see some obvious issues with this, namely being that elements in the ...
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Best statistical approach for psychological experiment
I have done an experiment where I have two groups of patients that received different treatments (Group1 received treatment 1, Group 2 received treatment 2). I measured a value that should be ...
user342084
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Estimation of ATT and average untreated effect on the untreated by OLS estimation
Suppose there are a binary treatment.
Based on the treatment, we can consider a treatment group and a control group.
Here, assume the following data generating process of potential outcomes:
\begin{...
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Interpreting an OLS regression where treatment is spatially associated to confounder
I am reading a study that is running an OLS regression to assess the effect of a treatment ($T$) on an outcome ($y$). Outcome $y$ is a disease, and the treatment group is strongly spatially associated ...
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In a RCT, what are the risk of selection bias if no allocation bias is present?
In the Wikipedia page about Randomized Controlled Trials (RCT), the procedures section states that RCT minimize selection bias and allocation bias.
My understanding is that selection bias "occur ...
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Treatment group size vs. Control group size for difference-in-difference estimation
I am reading an unpublished paper that employs diff-in-diff to firm data containing a total of 2598 observations. Of these observations, 2474 are in the treatment group and 124 in the control group.
I ...
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How to interpret output from "mediation" package - can I claim full mediation?
I have an outcome binary variable Y, a continuous mediator M, a binary treatment T and some covariates C.
I have a linear regression model for the mediator:
$ M = \alpha + \beta T + \delta C $
and a ...
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Is the "constant additive unit causal effect" assumption really needed to interpret a regression coefficient as the ATE?
I am reading Unpacking the black box of causality.
At page 768 there is written that, in order to uncover the ATE:
In observational studies, slightly more complex calculations may be needed, although ...
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Matching when there are missing data
In a treatment effects framework, I have a control and treatment group with some covariates on which to match (I'm using nearest-neighbor method).
The control group has a no missing data, but some ...
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Please help - completely stuck on what model to use in analysing changes over time between groups
I am running an experiment in which I have three groups, and three treatments.
The treatments are three different temperatures, and I am testing how they impact DNA degradation in water.
I.e. Group ...
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How to prove that one-sided non-compliance implies $E\left ( y|z=0 \right )=E\left ( y_{0}|z=0 \right )$?
Let $d \in \left \{ 0,1 \right \}$ denote the treatment status with unity indicating that the individual has been treated and let $z \in \left \{ 0,1 \right \}$ denote a binary indicator for whether ...
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Can ANOVA be run for groups with n=3 observations (R)?
I have an experiment comparing multispectral data for 3 different varieties of crops with 4 different fertilizer treatments. The experimental design is a randomized-complete-block design, with each ...
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IPTWs for Multi-category treatment, how to handle a multi-category mediator
I have a multi-category treatment for which selection is adjusted for using IPTWs. My concern regards a multi-category mediator that occurs post-treatment, but which also co-occurs with the outcome. ...
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Checking if treatment is effective without control group
I am experimenting with few treatments to see which one is effective. I do not have luxury of control group to compare against. In such scenario, is there any method to see if the treatment has been ...
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Are healthy patients an appropriate control group?
I am working on a study where patients with a chronic disease received a treatment. The goal is to determine the effect of the treatment on various outcome variables. I have pre and post data (before ...
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Standard Error of a formula
If I do have 100 samples of irrigated plants (labeled from 1 to 100)
and 100 samples of non-irrigated plants (during 5 days) (labeled to 101 to 200) from a drought tolerant specie
and
100 samples ...
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Understanding the perfect randomization assumption in treatment models
I have a basic question on the relation between counterfactual outcomes and treatment.
Notation: Let $D$ denote the treatment, taking value in $\{0,1\}$ where $D=0$ means untreated and $D=1$ means ...
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201
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Statistical Modelling of a complex experimental design
I have the following experimental design, and am quite uncertain which statistical approach would be the best to investigate my data.
I have three experimental treatments of my participants and would ...
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Interacting treatment variables with independent variables in matched samples
Can we interact the treatment variables with independent control variables that have been used for matching?
I have a binary treatment variable called 'medicine'. It indicates whether a person ...
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369
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How to chose covariates to adjust for in a regression analysis
I am running a regression analysis where my primary interest is to see if the outcome differs by the group (treatment vs. control). However, I have some 80 other clinical and socio-demographic ...
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Test for significance before testing
I got a question regarding the binomial distribution and testing for significance in general.
I need to divide a dataset into a treatment group (with phone call) and a control group (no phone call). ...
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Difference-in-Difference to identify treatment effect, with the treatment switched on/off?
In a classic DID model, the policy (or the treatment status) stay, once switched on, the same across the observation periods. That is, you have some units that are all untreated before the observation ...
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Modeling decaying treatment effects
Suppose I want to measure the effect of tornadoes on voter turnout at the county level. I suspect that counties that experience tornadoes will have lower voter turnout in the subsequent election than ...
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Difference in difference model with multiple time periods and treatment/control pairs
I am trying to estimate a difference in difference model with 10 time periods (t=10) and many different plots of land, which are the unit of observation. Each plot of land which becomes treated at ...
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Is a Mixed ANOVA the same as a combination of between ANOVA + repeated ANOVA + between ANOVA?
In my study involving three conditions (control, treatment 1, treatment 2), I am interested in measuring 2 DVs at a pre- and post-exposure. So effectively a 3x2 design (participants randomly allocated)...
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The implications of non-random allocation of intervention
I'm trying to understand the implications of an intervention which is not randomly allocated in a quasi-experimental setting. The intervention is receiving a license for shale gas exploration in the ...
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ANOVA - Do I use raw or aggregate mean data to compare groups
Here is my study design:
there are four soil plots - A,B,C,D
each plot is sampled for soil moisture at 15 locations
this soil moisture sampling is done for 10 rain events
I need to compare the soil ...
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Validity of conclusion of statistical tests when comparing two groups of observations in an experiment
I am just reading the results of an experiment, and I am having a hard time estimating their validity.
In the experiment, several participant had to perform a certain task twice, once with the ...
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How to analyze the longitudinal effect of blood pressure and its treatment on outcome
Say I have an observational dataset over 20 years with blood-pressure measured each year for 1000 men.
Each year a decision is made whether to start antihypertensive drug A, drug B or continue ...
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Difference ATE and ATET?
I have some problems understanding the difference between ATE and ATET and the Selection Bias. To explain what my understanding is I have done the following representation so you can correct me:
We ...
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Dynamic treatment timing in a panel-DiD framework
I have a question regarding the timing of treatment effects and how one could use the difference-in-difference estimator on a panel data set.
Let me begin by saying that I have a big firm level ...
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How to deal with dropouts from a waiting list control group?
Many treatment studies compare a treatment group with a waiting list control group, for example to adjust for spontaneous remissions. Unfortunately, many more participants drop out from the waiting ...
user14650
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Average treatment effect on the treated
There is something conceptual I don't understand with average treatment effect on the treated. Say you have two binary outcomes $Y_i(W_i)$ in which $W_i$ is either 0 or 1 (treatment). So I either ...
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How to calculate the post-hoc treatment effect depending on initial burden of patient
I have longitudinal data following patients before and after a dichotomous treatment. Exploratory analyses strongly suggest that the effect of the treatment depends on the initial burden of the ...
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