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Questions tagged [intervention-analysis]

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

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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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1answer
19 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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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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25 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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29 views

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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14 views

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
21 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
69 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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22 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
73 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
55 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
34 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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59 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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1answer
69 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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37 views

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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28 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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28 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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115 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
43 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
164 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
568 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
264 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
120 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
119 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
45 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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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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55 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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225 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
32 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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451 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
84 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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454 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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429 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 ...
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2answers
245 views

How to model and visualize time-delayed effects of a variable?

I am working on measuring and plotting a health metric (e.g. Blood pressue) everyday (multiple times every day). I tag everyday's reading with some tags that happened that day e.g. [run, smoke] (...
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1answer
58 views

Testing association in meta analysis

I am doing a meta-analysis where I have the baseline and 2 months post-intervention measurement of a continuous variable (say a) for two groups (control and intervention). I also have measurements for ...
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1answer
71 views

Intervention Time Series Analysis Regression Choice?

I have a times series dataset that combines trends on twitter with discrete occurrences of violence. The dataset goes from 1/1/2015-10/30/2016 and each observation is a date. For each data there is a ...
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1answer
983 views

Test for the significance of the effect of an intervention in a time series

I am looking for the best approach to test for the significance of the effect of an intervention that occurred at a known time on a time series data. Using a toy dataset as an example, I have come up ...
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2answers
716 views

Extracting the effect of TV ad campaign on time series with seasonality

I was wondering what would be the best way to measure the effect of a TV ad campaign on sales (phone and online) and other metrics such as website visits. One could argue that most of the effect of ...
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1answer
38 views

What statistical test to use for this scenario?

Here's my problem. --ONLY One group-- All fill-out pre-test. All participants given intervention. Complete a post-test. Return in 2-weeks to complete another post-test to determine if intervention ...
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1answer
666 views

Using Google Causal Impact package to assess the significance of a planned intervention

I am using the Causal Impact package in R to infer the causal effect of an intervention in some data which are highly correlated and seasonal. Specifically, i got 17 days of hourly data, intervetion ...
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2answers
634 views

Longitudinal analysis with intervention

I hope this question fits the topic of this forum. Consider a dataset - a cohort of N subjects (s_i), with measurements at fixed time points (t_i) (every week) of some quantity (Q_ij) . Then after K ...
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Intervention analysis with multiple time series of daily counts

I have daily time-series data over the same 10 year period for the number of visits of specific individuals to a certain website, i.e. number of visits per user per day. The visitors are from a ...
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2answers
400 views

Method for quantifying intervention effect in time series

How can the magnitude of an intervention be quantified in a segmented time series regression? I am attempting to replicate the methodology of Decline in pneumonia admissions after routine childhood ...
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1answer
419 views

ARIMA-GARCH instead of ARIMA for intervention analysis

I'm looking to carry out an intervention time series analysis on the S&P500 to see how presidential elections affected the stock market. I want to use an ARMA-GARCH process to model S&P500 ...
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1answer
155 views

Using a function of intervention time as a covariate in arimax

I am trying to estimate the impact of an intervention on a time series. The problem is that the intervention effect looks curve-linear (i.e. increasing, plateauing, and then decreasing), and I am ...
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71 views

Evaluating intervention statistics for a given observation

My desired procedure is the following: A time series is imported. One or more observations are flagged as events/outliers. An automated procedure determines what type of outlier each event is and its ...