Statistical Analysis Stack Exchange
Statistical Analysis Stack Exchange

Questions tagged [baseline]

A base measurement for comparison. Usually a measurement prior to treatment, of a control condition, or of the assumed population.

A baseline is a starting point or basis of comparison for something. To test how a class's performance improves over time, a researcher might begin with a baseline showing their current scores and grades.

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How simple should a Baseline model be?

I was making baseline model and was wondering how much time I should spend on it. I've found a lot of article about the purpose of a baseline model, for instance; A baseline takes only 10% of the time to develop, but will get us 90% of the way to…
Adrian Evensen
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Is there a mathematical proof for change being correlated with baseline value

It is shown in answer here and at other places that difference of 2 random variables will be correlated with baseline. Hence baseline should not be a predictor for change in regression equations. It can be checked with R code below: > N=200 > x1 <-…
rnso
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Baseline controls for clinical trials in mixed models through random effects?

I'm analyzing multisite clinical trial data with mixed models. I have (a) a continuous DV, (b) a grouping variable (treatment vs control), (c) baseline scores for the DV, (d) a time variable (baseline, and three additional measurement occasions),…
SometimesZero
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Analyzing impact of baseline value on change score using lmm

I'm using a big clinical data set with a the evolution of a continuous lab value over time being the dependent variable and I am interested in the impact of the baseline of this value on this evolution. I have come across some similar qustions in…
user311327
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Significant difference between randomized groups at baseline?

A collegaue and I are conducting a pilot study in a school, the aim of which is to assess whether an "alternative" educational tool is more or less effective than traditional teaching methods. Students in each participating class were randomly…
Bálint L. Tóth
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how to calculate median follow-up time?

I have a hospital based dataset which conatins information on patient details. Right from their visit, drugs, diagnosis, lab tests, and death info etc. So, now I would like to compute their follow up time from the date of the 1st visit to last visit…
The Great
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How to handle large baseline difference in a randomized trial

I have results of a randomized trial where 200 participants were randomly allocated to 2 intervention groups and outcome evaluated 1 month later. I believe baseline differences between 2 groups are now not subjected to hypothesis tests. However, I…
rnso
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Why we cannot take baseline as predictor for change in this case

It is generally recommended that baseline should not be kept as predictor if change is outcome variable. Explanations for this have taken both baseline and final values as random (e.g. see here). However, final value is likely to be close to and…
rnso
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What are the advantages and disadvantages of including a baseline measurement variable in longitudinal data analysis?

What are the advantages and disadvantages of considering a baseline measurement variable in longitudinal data analysis? (A baseline variable could be the number of seizures each patient had per measured day before the study began.) In a…
user271077
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Is it a problem if my model does not perform as well as the stupid model?

Usually what I see is that the baseline accuracy and the base model have different accuracies so then the goal is to clean the data and do some feature engineering etc to build a model that performs better than the baseline. Everyone including my…
Edison
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Baseline adjustment when both pre- and post values are subject to left-censoring

Assume $X$ is a binary treatment variable, $Y$ is a continuous variable measured pre- and post-treatment $(Y_{pre}$, $Y_{post})$, and $Z$ represents the remaining covariates. Both $Y_{pre}$ and $Y_{post}$ are subject to left-censoring. Does anyone…
andrjens
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How to check baseline covariate balance after variable ratio matching?

In my case, each active subject is matched to a variable number of control subject. The way I can think of is to first average across the control subjects for the same active subject to make a 1: 1 matched sample so that it is easy to get mean…
hehe
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First Time Point in an LS Mean Plot with Baseline Control

Hoping you can help me understanding a request that my supervisor would like me to do in an LS Mean plot. My model is the following in lme4: DV ~ Group + Time + Group x Time + BaselineScore + BaselineScore x Time + (1|Subject) + (1|Site) Where…
SometimesZero
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Which variable to take as reference category?

I'm doing a research about the relationship between investment risk tolerance and demographic factors such as age, generation, survey year, and control variables (including education levels,...) and I have 2 questions: I have already categorized…
Long Duong
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Keeping baseline as predictor with change score as outcome in this peculiar scenario

It is generally recommended that baseline should not be kept as predictor if change score (final - baseline) is the outcome variable. However, there are many instances in biomedical research when one feels that baseline may be affecting change and…
rnso
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