Questions tagged [control-group]

In a comparative experiment a control group is one which does not receive the active treatment

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PanelMatch. Help me [closed]

I value longitude data RLMS. I have data https://drive.google.com/file/d/1jyTMXXY1nBmfheR9XA_5a1znKsvnYC_J/view?usp=sharing I want to divide people into two groups:the treatment group and the control ...
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22 views

What does 'control' in controlled experiment refer to?

Does 'control' in controlled experiment refer to: Having a control group for comparison, i.e "an experiment or trial that uses controls, usually separating the subjects into one or more control ...
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6 views

Which statistical design/method would be best to analyze data with an internal healthy control?

I have a group of subjects who received 2 interventions over a certain amount of time on one half of their body, with the other half remaining as a control. The design of the study was as follows: ...
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31 views

Do control variables need to be added for the following parallel trends assumption test for diff-in-diff?

I completed the following test for parallel trends Difference in Difference method: how to test for assumption of common trend between treatment and control group? However, I am unsure as to whether ...
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41 views

Treatment group is omitted because of collinearity

I am using a difference-in-difference strategy with fixed effects -xtreg...,fe robust-. I am using as my treatment group mothers whose youngest child is younger than one. I am investigating a few ...
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22 views

Using clustering to determine a control group in A/B testing?

Problem described below: We have 5000 customers. We ran a test on 50 of the customers over a two week period. The operations of our business restricted us to running the test on a specific group of ...
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40 views

In what situations is a one sample T-Test superior to a two sample T-Test?

I'm trying to make a case for more use and respect of one-sample t-test in medical studies (which are generally looked down upon, wrongfully so imo). I see that in general medical studies prefer at ...
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47 views

Confidence interval around effect size for pre-test post-test control group design

I'm evaluating different experimental studies that all included an experimental group, a treatment group and a two measurements (pre-test, post-test) and usually report the mean, standard deviation ...
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32 views

How to compare 2 groups to show significant differences?

I am conducting an experimental study. I have 2 groups: The first group contains 3 healthy persons and the other one contains 3 patients (sick people). For each person of the study, we collect several ...
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67 views

Meta-Analysis without a Control Group

I am conducting a systematic review and meta-analysis which is investigating health-related quality of life in a particular patient population. I am having difficulties with conducting the meta-...
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10 views

Multi-arm RCT Sample Size External and Internal valid

I am trying to figure out the sample size for a multi-arm Randomized Control Trial (non-clinical) that will have internal validity and representative of the population, say; population X Any ...
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9 views

Experimentation Time series - Find a control group whose mean follows closely the test group

I'm conducting an analysis from Jan to Dec where my test/treatment group is the combination of 5 stores with sales per month. The main objective is to find a control group of 10 stores over 150 ...
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129 views

How to measure Sales lift for a campaign without experimental design?

I want to be able to calculate Sales Lift for a campaign conducted but prior to campaign no control group was established. So, I cannot measure the impact on Sales because of campaign to treatment ...
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32 views

How to treat a duration of chronic disease

I have a data set that contains information about healthy dogs; dogs that have chronic heart disease; and dogs that have the same disease, but are considered as a long-livers. (All dogs in this ...
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12 views

Control group in regression discontinuity design

I apologize for being a bit vague, I'm trying to protect my ID a bit. I am looking at regression discontinuity design for a program evaluation. Specifically, within a clinic, we would like people ...
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152 views

Group By and Scale Data vs Scaling Data Without Grouping

I have a panel data set that covers 20 earnings dates for 50 companies. I would like to know if I should scale data by the ticker or just scale the data without grouping. What would be the pros and ...
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Pre-Post Analysis and Accounting for Task Difficulty

The study We have a real world pre-post design where some people were trained and others were not trained. The goal is to determine if the training worked and improved performance overall. The ...
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53 views

What is the name of the “test” for testing the similarity of control group and experiment group?

In a simple statistical analysis involving a control group and an experiment group, the research must demonstrate that before the experiment, the control group and the experiment group are the same or ...
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66 views

diff-in-diff with continuous treatment vs cut-off point (and 2 periods)

I have panel data for a number of counties for two years only (t = 1,2). The treatment, let's assume it's a policy implementation programme, happens in between year 1 and 2 and it is a continuous ...
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29 views

How to incorporate the customers leaving (addition of new ones) in the measurement of treatment effectiveness?

Consider I have taken a random sample for forming control group in month of January with sample size 5k and treatment group size being 95k. I am Sending offers to treatment group which are intend to ...
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33 views

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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25 views

choosing a control as the *absence* of a condition in a retrospective longitudinal study

Let's say I am interested in cancer patients (or any other disease), and I am looking at their behavior prior to cancer onset - in a retrospective, longitudinal study. Now I want to design a control ...
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37 views

Different sample size of control and test groups

Hope someone can help my question: I have a survey study with one control group and one test group. Each is set to have 500 completes. However, we are short in sample in one group: Test is 350 and ...
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32 views

Is chi squared test of independence correct with control group?

I'm analyzing some data from an experiment in which passage of time between conflicting tasks is my independent variable and one of my dependent variables is a dichotomous one ("A","B"). I also have a ...
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33 views

Difference-in-difference analysis: more than one control group

I'm doing a difference-in-difference analysis of the impact of financial incentives on healthcare delivery. I have one treatment group (where there were financial incentives), and two separate ...
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27 views

Dealing with self-selection in the treatment group

I wanted to do a Randomized Controlled Trial for a new curriculum that was announced in my area. The issue is, certain teachers, under the organisation that I'm working with, have selected to teach ...
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Repeated measures with rotation of subjects within groups

I was wondering if you could help with the interpretation of a potential experimental design. We are testing two versions of a 'group' exam, score (out of 100) being the outcome variable, aggregated ...
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1answer
28 views

Before/After unpaired study with control villages analysed in R

For the implementation of a project, we have been following household access to services in two groups of villages, one an intervention group (I) and one a control group (C). Access as a Yes/No ...
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93 views

Measuring incremental revenue / uplift

I run a campaign with an experimental design setup. The target and control group is representative and split 70/30. The target group receives an email communication The dynamics of the campaign ...
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48 views

Standardization based on subsamples

I need to analyze data on the cognitive performance in a sample of participants divided into clinical (36 participants) and non-clinical groups (~100 participants). What would be the correct ...
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1answer
74 views

Splitting panel data into subgroups

I have a (an unbalanced) panel dataset of individuals over different periods of time (one time period = one month). I'm attempting to analyse the effect on the level of activity of the individuals of ...
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35 views

Pursuing meaningful questions about pre- post- intervention outcome measures in single condition treatment

If you are not fortunate enough to have a control group and have a single condition only, what meaningful questions can you ask about the change in pre to post intervention scores? If ANOVA or ANCOVA ...
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1answer
37 views

comparsion of treatment groups based on different controls

I have experimental results from two days where I wasnt able to keep the same conditions from day1 to day2, so I have two sets of data: control day1 -- 2x treatment groups day1 control day2 -- 2x ...
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1answer
64 views

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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147 views

Control group selection

I am currently migrating some code from SAS to Python. I am trying to do the following in python: I have two groups of customers: those that were exposed to a campaign, and those that were not (the ...
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44 views

What is the Level of Evidence of “simultaneous self-controlled study”?

I guess this is an undefined thing, and would like to know your opinion. What is the Level of Evidence (as defined in the link by Oxford https://www.cebm.net/2009/06/oxford-centre-evidence-based-...
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256 views

Diff-in-diff with mactched control group

I want to run a diff-in-diff model. To choose an appropriate control group, I use a nearest-neighbor matching model based on several determinants of the outcome variable that I study. I was ...
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1answer
70 views

Diff in diff model with multiple treatments in multiple perdiods?

Can I estimate a diff in diff model to compare the effects of two different treatments that apply in different time periods in different countries? I have 30 countries for an average time span of 34 ...
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3answers
1k views

How to calculate the p-value of a test, that checked for a binary property?

16081 subjects were randomly assigned into two groups: test group: 7916 subjects control group: 8165 subjects Only the test group was exposed to something. During the test period 10 subjects of ...
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2answers
693 views

How to choose Control groups for Causal Impact algorithm?

I'm running an experiment and want to use the Causal Impact function to assess how well it performs. I have 10 different cities. I'm looking to find out what is the best method for choosing which ...
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97 views

Pre-treatment period in difference-in-differences model

I want to evaluate the consequences of a policy change using a diff-in-diff setup. I have quarterly data over ten years before the treatment ($t_{-10}$, $t_{-9}$, ..., $t_{-1}$) and ten years after ...
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1answer
185 views

Meta-analysis in R without control group? Purely improvement of symptoms

I’m currently trying to perform a meta-analysis in R via the metafor package using data that does not have a control group. In this case, I am looking to see ...
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1answer
75 views

How to compare several means to control when the distribution is not normal and sample sizes are unequal?

I have a large dataset (n = 170,000), distributed roughly equally among 5 groups (each is 34,000 ± ~1,000). I want to compare whether the means in any of the first 4 groups are different from the ...
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118 views

How does using control variables in experiments affect the bias-variance trade-off?

Following up on the post, Using control variables in experiments?, I wonder how this connects with the usual bias-variance trade-off? That is, to minimise the MSE one must trade off the gain from ...
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Comparing a traditional and technology based tool

I am trying to compare a printed word dictionary with a digital dictionary that included added features like sound and video feedback. For this I have selected 60 participants and asked 5 questions (...
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Determining if a test measurement is from an empirical control distribution

I have a sample of 100 measurements from a control population. These measurements are not that close to a normal distribution. I also have made a single measurement that received a treatment. Is ...
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1answer
22 views

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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1answer
105 views

Difference-in-Differences with Aggregated Data

I have access to aggregated data of a population for a 1,5 year period. I am interested in conducting an events study to check whether the implementation of a certain treatment will affect the ...
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42 views

Redemption proportion test: Big control group used several time or split into several control groups?

I'm preparing a test of proportions regarding a campaign redemption of several groups which have all common "demographics" but have been stimulated into different ways. At the same time I have a big ...
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Statistical test to use? [duplicate]

I am currently conducting a quantitative experimental research wherein 2 groups will be my participants. The research aims to determine whether or not Code-Switching is an effective tool to achieve ...