# data problems

**URL:** https://discourse.datamethods.org/c/stat/dataprob/19.md

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## [About the data problems category](https://discourse.datamethods.org/t/about-the-data-problems-category/42)

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**Author:** [@f2harrell](https://discourse.datamethods.org/u/f2harrell)\
**Replies:** 0

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statistical approaches dealing with missing data and measurement error

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## [Missing inclusion criteria data in registry-based studies](https://discourse.datamethods.org/t/missing-inclusion-criteria-data-in-registry-based-studies/13570)

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**Author:** [@martinspn](https://discourse.datamethods.org/u/martinspn)\
**Replies:** 3\
**Last updated:** [May 17, 2024, 10:20pm UTC](https://discourse.datamethods.org/t/missing-inclusion-criteria-data-in-registry-based-studies/13570 "2024-05-17T22:20:38Z")

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I’ve been working with registry data and sometimes one of the clinical baseline variables (pre-stroke modified Rankin Score - mRS) is missing. The mRS after 90 days is also the most common outcome in our field. The usua…

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## [Inferences from summary data - without seeing the data for a Cox PH model, do chi square tests tell us anything?](https://discourse.datamethods.org/t/inferences-from-summary-data-without-seeing-the-data-for-a-cox-ph-model-do-chi-square-tests-tell-us-anything/6955)

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**Author:** [@DRG](https://discourse.datamethods.org/u/DRG)\
**Replies:** 5\
**Last updated:** [July 24, 2023, 7:03pm UTC](https://discourse.datamethods.org/t/inferences-from-summary-data-without-seeing-the-data-for-a-cox-ph-model-do-chi-square-tests-tell-us-anything/6955 "2023-07-24T19:03:40Z")

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Hi folks - this might be a daft question, I asked similar on Cross validated yesterday and got a suggestion to post his here, so sorry in advance if similar has been asked before. Consider a paper like this, which report…

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## [Using MICE to impute missing data across join of two data sets](https://discourse.datamethods.org/t/using-mice-to-impute-missing-data-across-join-of-two-data-sets/5926)

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**Author:** [@woodwards](https://discourse.datamethods.org/u/woodwards)\
**Replies:** 6\
**Last updated:** [September 1, 2022, 3:30am UTC](https://discourse.datamethods.org/t/using-mice-to-impute-missing-data-across-join-of-two-data-sets/5926 "2022-09-01T03:30:57Z")

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Hi all, first time poster here. I’m a data scientist working in the New Zealand dairy industry. I have a problem where I have two data sets, the first is about 140000 rows and has region, year and annual\_quantity. The s…

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## [How to handle large number of observations below LLOQ](https://discourse.datamethods.org/t/how-to-handle-large-number-of-observations-below-lloq/2682)

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**Author:** [@daszlosek](https://discourse.datamethods.org/u/daszlosek)\
**Replies:** 4\
**Last updated:** [December 11, 2019, 11:17am UTC](https://discourse.datamethods.org/t/how-to-handle-large-number-of-observations-below-lloq/2682 "2019-12-11T11:17:31Z")

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I recently encountered a small cross-sectional retrospective study that was quite interesting. 25 subjects were reported have been exposed to some agent and their serum was collect (in 1999) 13 clinically healthy contr…

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## [How to derive survival time on anonomised dates](https://discourse.datamethods.org/t/how-to-derive-survival-time-on-anonomised-dates/1219)

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**Author:** [@PaulBrownPhD](https://discourse.datamethods.org/u/PaulBrownPhD)\
**Replies:** 0\
**Last updated:** [January 10, 2019, 3:42pm UTC](https://discourse.datamethods.org/t/how-to-derive-survival-time-on-anonomised-dates/1219 "2019-01-10T15:42:55Z")

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i wonder if there is a convention and a google search is not revealing much. Date of birth has been anonomised using july for month. Obviously this leads to some negative survival times. I don’t want to simply set negati…

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## [Differential misclassification of the outcome (by exposure status)](https://discourse.datamethods.org/t/differential-misclassification-of-the-outcome-by-exposure-status/862)

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**Author:** [@tm\_epi](https://discourse.datamethods.org/u/tm_epi)\
**Replies:** 2\
**Last updated:** [October 29, 2018, 4:59pm UTC](https://discourse.datamethods.org/t/differential-misclassification-of-the-outcome-by-exposure-status/862 "2018-10-29T16:59:06Z")

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Hello! I work on a linked health administrative dataset of all known people living with HIV in a given geographical area; an HIV clinical database has been linked to several administrative data sources. As is typically d…