Questions tagged [intervention-analysis]

Intervention analysis estimates the effect of an external intervention on a time-series.

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Two simultaneous time series vars. Want “confidence” intervals for one's prediction (not forecast per se) of the other

Let me know if this is a duplicate. This seems to differ from other time series questions I've seen in that I'm not trying to forecast the future. Maybe that will mean only a difference in the ...
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intervention analysis with multivariate regression

Does intervention analysis make sense when one has multiple external regressors? How would one know if say, a level shift, is caused by a combination of external regressors or by a change in a law ...
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elastic net with random interventions

Since elastic net gets rid of regressors that do not correlate, would it make sense to randomly put in a bunch of interventions (pulses, level shifts, ect)? If the intervention is not needed, won't ...
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38 views

CausalImpact Conflicting Results - Posterior prob. v Confidence Interval

I'm getting conflicting results from a Causal Impact analysis I'm running. The 95% C.I. indicates that 0 is included and thus the impact is not significant; however the Posterior Probability is <....
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How should I specify seasonality in CausalImpact? [closed]

I am working with the Python implementation of Google's CausalImpact package. My data is at daily frequency (365 observations per year); however, to inspect the effect of intervention, my pre-period ...
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20 views

Pre post intervention analysis

I have a theoretical question about a fabricated before-after analysis with Intervention and Control groups based around a new testing method. In addition to the treatment groups and time (before and ...
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1answer
20 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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37 views

Before - After survey testing with a control group, how to analyse

Sample size in intervention area n=800 For the purpose of measuring progress on the proportion of families having access to a service (yes/no variable) by households in eight intervention villages, a ...
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Testing Response Model

I'm thinking about strategies to examine how well a churn model performs. And, I know one question I'll receive is can we just target customers in the top decile of the churn model to evaluate model ...
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Estimating Policy Effect with a Logit

So I am testing a policy which was introduced in a country trying to incentivise people to stay employed at older ages (beyond the retirement age of 65). As such, they introduced a bonus where people ...
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1answer
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Testing an intervention by repeated measure of opinion before and after the intervention

How can we test the null hypothesis that an intervention has no effect on opinions for 44 people. These opinions were measured as frequencies in 3 categories (A, B, C) before and after the ...
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Medical or Intervention Study

A friend and I are trying to better understand proper design of a randomized trial, from beginning to end, with an eye to creating an informal one showing the benefits of a particular academic ...
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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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29 views

Does statistical significance impact uplift calculation for marketing campaign

I'm trying to understand 2 things in relation to calculating uplift from a marketing email campaign: Impact of statistical significance Impact of highly skewed data on calculating uplift The ...
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51 views

intervention analysis on several time series samples where intervention occurs at different times

I have quarterly sales data for ~80 products spanning 4 years. I also have 16 different external interventions, where one or multiple of them have occured on the products on different dates during the ...
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29 views

Statistical analysis for quasi-experiments

This is my first message on this forum. I hope I am not doing any mistake. I must analyze data obtained after a quasi-experiment and I am not sure how to proceed. The experiment has been carried out ...
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197 views

Interrupted Time Series Analysis with multiple Intervention timepoints

I was wondering if it is possible to do a interrupted time series analysis with an intervention that is introduced and removed at specific intervals throughout the time-series. All of the literature ...
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Determine how long the effect of x on y may last in time series data

I have a time series dataset that contains variable x and y per month (180 rows). x represents incidents that happen infrequently and y is a continuous variable. However, when there is some incident y ...
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Can I compare daily averages using a T test?

Pretend you had a sales group that was required to perform a bunch of administrative work for every prospect they contacted. E.g., entering the prospect's contact info into a CRM, researching the ...
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1answer
29 views

Validating A Model On Pre-Test Post-Test Design

I am phd candidate at primary education department. My aim is to validate a model but i have not find a exact answer yet. I have 2 groups. (Actually 4 but only 2 of them are going to use to validate ...
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1answer
71 views

Are high schools dumbing down their exams? I don't know. How can we find out?

I have a large-ish longitudinal dataset of high school and college course registration and grades. I want to test the assertion that high schools are "dumbing down" their courses to meet graduation ...
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24 views

How to manage fusion of firms or countries in time series analysis

I am working with time series analysis and one of my series is loans of a very large bank between 1970 and 2015. However in 2000 that bank, acquired a smaller bank. I only have the data for the big ...
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30 views

Methods to account/correct for dropouts in intervention study

I have depression scores for patients before and after intervention, there is no control sample. I want to assess if demographics have an effect on recovery, and I was thinking of doing a linear ...
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3answers
86 views

Hypothesis test for intervention with class imbalance before intervention. Alternative to McNemar

I want to assess an intervention to cure a disease. An example is described by the following matrix: ...
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1answer
79 views

How to statistically determine if there was sales lift?

Say my company is about to make some changes that they expect will increase sales and customer acquisition in current markets, what would be the best way statistically to determine if that lift was ...
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3answers
35 views

Pre- and post-values for two groups randomly assigned to either intervention or control

My project aims to see if sitting for an hour temporarily slows movement in patients with movement disorders. I have two groups (20 sick patients and 10 healthy patients) who are randomly assigned ...
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1answer
73 views

Can a random slope in a linear mixed model mask the effect of my intervention?

I want to assess the impact of my intervention in a repeated-measures design. I have subject as a random intercept in order to account for the dependence of measurements within subjects: ...
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91 views

Measuring impact of intervention using a counterfactual forecast?

I'm an economics student who's trying to dive into causality. I've tried looking into intervention analysis, but I can't seem to find many sources on forecasting using historical data as an approach. ...
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Analysis of Pre-post Likert-type scales: Intervention vs. Control group

I gathered the following data: Intervention group (n= 24, received treatment): pre- and post- scores of different psychometric questionnaires Control group (n=23, inactive): same questionnaires, same ...
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47 views

Time Series Data: Unequal Sample sizes

I have a dataset which consists of daily observations over a 3 month period for different variables. The data are aggregated so I do not have access to user level data. The problem is that the ...
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29 views

Determining relation between branding spend and sales growth

A company exports a units of product to a distributor in a foreign country. This distributor then sends units to dealers across the country who run shops that sell the product. Until May 2017, ...
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124 views

Statistical Significance of Time Series Data pre and post intervention

I am currently working on data in which I have to see the rate of entry of children to a foster home is statistically significant or not before and after a welfare program was implemented. I got the ...
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1answer
49 views

Looking for techniques to understand the impact of a discrete events (interventions) on a continuous response variable in time series

I am trying to model the effect of one or more discrete interventions (e.g., taking a pill, attending therapy) on a continuous outcome (e.g., pain level of a patient over time). The features are ...
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1answer
221 views

Is a Chow test appropriate for this intervention analysis?

I am fairly new to R was wondering if this approach was appropriate. Sorry if I forget anything in my question. I have long-form panel data for 15 years (2001-2015) for hundreds of counties and ...
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1answer
790 views

Comparing slopes in a time series following an intervention

There are lots of related CV questions to the title above, but I'm looking for some clarification on a specific approach, and some explanation. The set up is as follows (adapted from another question)...
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1answer
1k views

Linear Regression vs. ARIMA

I have a data set that was sampled at a high frequency relative to the speed over which changes are expected to occur. This has resulted in high autocorrelation between adjacent values upto a lag of ...
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1answer
376 views

Repeated measure ANOVA vs independent 2-sample t-test

I have this data where I have a control and an intervention group. For both of these two groups, I have a continuous outcome measured at baseline $(y_0)$ and at 1 month $(y_1)$. To test for the ...
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1answer
147 views

Casual Impact Analysis with Linear Regression - Interpreting Results

I have two groups of customers. One received a promotion another did not. I want to determine the effect of the promotion. I created a simple linear regression with a dummy variable for weekend. ...
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2answers
132 views

How to analyze trends of multiple patients' data before and after an intervention

I have data for 200 patients' blood sugar levels before and after an intervention. There are multiple readings both before and after the intervention. In order to see if the intervention had a ...
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1answer
39 views

Choosing a test to compare means within a sample

I have blood sugar values for diabetic patients over the past few years from a clinical practice. Half way through the observation period, a treatment intervention was applied to all of the patients. ...
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1answer
48 views

Determine if there is an influence of newspaper articles on stock quotation

Lets assume there is a company called "XY", which is listed in the NASDAQ. Lets further assume that newspapers are frequently reporting about company XY, either in a positive, neutral or a negative ...
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92 views

Comparing pre/post percentage change between pairs of random samples

I am studying cycling rates along a street that recently received a bike lane. The data I have consists of 4 random samples of people intersected on the sidewalk. For each person, we know if they rode ...
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59 views

Which is best method and interpretation for a single-group pre-post model with interactions?

I have some one-group pre-post data where the outcome is a score and an IV of interest is the whether or not the subject has performed the task in the past. I am looking at this in a few ways and am ...
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270 views

Calculating Cronbach's alpha for pre-post scales separately or together?

I am measuring a self-efficacy (SE) score by measuring 7 sub-scales for pre and post intervention.For example, for a participant, I have the SE score by measuring 7 sub-scales before the intervention, ...
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1answer
34 views

Using change in rank to assess effectiveness of an intervention

Is it possible to assess the effectiveness of a classroom intervention by: Taking scores from an entrance exam administered before the intervention Ranking these scores (i.e. 1st, 2nd, 3rd, ...) ...
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544 views

Stratified Paired T-Test for One Group

I have pre/post data where all subjects underwent the intervention. The outcome is a score. I am also looking to stratify my analysis by gender. I understand I can stratify my paired t-test in SAS via ...
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1answer
93 views

one group pre/post test

I am conducting a one-group pre-intervention / post-intervention test. All the subjects completed the intervention as otherwise there would be ethical concerns. Is there any test other than a paired t-...
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524 views

Interpreting ARIMA for Interrupted Time Series Analysis

I want to test for efficacy of an intervention. I have pre- and post-intervention data and I used auto.arima to find the best fit for the two data sets. I'm stuck ...
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491 views

Autoregressive model problem with multiple dummy variables

I am conducting an event study, and I am trying to use dummy variables in my AR(4) model for stock returns to observe any abnormal returns. Each dummy takes a value of 1 for one specific day, zero ...
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1answer
110 views

Independent vs Dependent Regression correlation?

I am trying to look at stock tickers. For example "MSFT" is the stock ticker for Microsoft. Using the package quantmod, an R package, I can get the latest 365 days of stock prices. Each quarter a ...