Questions either on modeling COVID-19 (e.g., epidemiology), or on including COVID-19 as a predictor in models for other variables. Questions using this tag also should have another tag (or several) to indicate the statistical content.
Questions tagged [covid-19]
44 questions
32
votes
5 answers
How can you account for COVID-19 in your models?
How are you dealing with the coronavirus "event" in your machine learning models?
Let's say you used to predict the number of sales each month. The virus affected your results last year and it will affect for at least a couple of months. So your…
dsbr__0
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12
votes
1 answer
Should AstraZeneca's results be discounted?
This question is in regard to AstraZeneca's phase 3 clinical trial on the effectiveness of their COVID-19 vaccine.
Patients were randomized to a two dose treatment group compared to a two dose placebo group. But a large portion of the treatment…
Michael R. Chernick
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10
votes
1 answer
How well do Covid-19 forecasts work?
I hope this question is in the scope of CrossValidated (I think so because it is in the end about statistical analyses and machine learning, I am not looking for individual opinions but for reviews or surveys, for example based on pre-registered…
Arne Jonas Warnke
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10
votes
3 answers
Why is $R_t$ (or $R_0$) and not doubling rate or time the go-to metric for measuring Covid-19 expansion?
In my head, the natural way to measure the expansion speed of an epidemic across populations of different sizes is simply fitting an exponential over recent infection numbers (with any strategy), getting a parameter $C$ for $I(t) \approx e^{Ct}$.…
Federico Poloni
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6
votes
1 answer
Analyzing Pfizer Vaccine Efficacy: Testing a Claim about 2 Proportions
I teach Introduction to Statistics and would like to show my students how to analyze the Pfizer Phase 3 Vaccine results. Testing a claim about 2 proportions is straightforward with the Pfizer data:
Given:
Group (1) is the placebo group;
Group (2)…
Christopher Donham
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4
votes
0 answers
How is the reproductive number R being calculated?
The reproductive number $R(t)$ quantifies the expected number of secondary infections caused by an infected individual at time $t$. Thus, an R number below 1 will be likely to stop a disease like Corona.
Is there a gold standard how to calculate…
Michael M
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3
votes
4 answers
How many data points for test set in a time series
I have a monthly sales data set from 2018 January onwards. I would like to know from expert what is the optimum train test split and minimum train test split. Also to mention that my data includes 2020 year data where the sales have been influenced…
Prasenjit Datta
- 31
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3
votes
2 answers
Baysian probability of false positive COVID-19 test
I am wondering what the probability of a false positive COVID-19 test would be in my city. I'm attempting to use Bayes Theorem to calculate this, however I'm getting very different results based on how I formulate the problem.
Here are the…
Erik
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- 3
2
votes
1 answer
Calculate probablity of Covid-19 infection from 2 positive and 1 negative tests
There are two Covid-19 tests
Test A: Sensitivity 92%, Specificity 99.7%
Test B: Sensitivity 97%, Specificity 99.7%
Assume a person takes three tests consecutively (i.e. right after another), in the order A, A, B.
The results are as follows:
First…
ChrisC
- 123
- 3
2
votes
2 answers
What specific endpoint(s) were used in determining the efficacy of the Pfizer and Moderna Covid-19 vaccines during the FDA trials?
I have been searching over various articles and pages from the CDC and elsewhere, but I haven't yet found a specific description of what endpoint(s) were used to define efficacy in the FDA Covid-19 vaccine trials for the Pfizer or Moderna vaccines.…
twhitney
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2
votes
1 answer
Help Requested - Bayes' Theorem posterior odds > 1 when applied to covid test
I took an antigen test yesterday and was trying to create a tool to help me interpret the results via Bayes' Theorem. I used actual sensitivity and specificity numbers from the CDC, calculated odds of test results given presence of condition,…
tenaciousjeebs
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2
votes
1 answer
How trustworthy are biomarker estimates and conclusions in this covid vaccine paper?
My question is about the Correlates of protection against symptomatic and asymptomatic SARS-CoV-2 infection paper from the developers of the ChAdOx1/Vaxzevria vaccine. The paper establishes correlates of vaccine protection: biomarker levels that…
schrödingcöder
- 145
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2
votes
1 answer
Appropriateness of propensity score matching when treatment is determinsitic and exogenous (e.g., COVID restrictions)?
I recently came across this paper by Sibley et al. in which propensity score matching (PSM) was applied to examine the effects of COVID-19 lockdowns on well-being and government attitudes in New Zealand. Specifically, they treat COVID lockdown as…
Doctor David Anderson
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2
votes
2 answers
How can we distinguish the effects of a lockdown from those of a vaccine?
My question is related to Covid-19 specifically, but it can be generalized to any infectious disease. I am asking this since I am reading a lot of information on several Social Media regarding one specific vaccine which is widely used in my home…
wrong_path
- 607
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2
votes
1 answer
How statistically relevant are COVID information about the number of infections per day?
I am French and the restrictions in place in my country are driven by several indicators, including "the total number of infections per day". For reference, it is currently given as about 10000.
My general question is: how statistically relevant is…
WoJ
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