missing data


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missing data

EBM
A term used in the context of a clinical trial for:
(1) Data not completed or corrupted in reports and case report forms; or
(2) Data not captured when a subject withdraws from a trial.
 
Clinical trial reviewers are usually more concerned about non-captured data, as patients who are not improved or who believe they have experienced side effects are more prone to leave a trial, thus skewing the analysis of results if such analysis were only done on subjects who had continued with the trial. Trial designs therefore specify plans for how such missing data will be treated in analysis.
References in periodicals archive ?
The subject of the order is to enter missing data from supplementary reports (mapping of measurement results) in the range of renewals of signs or designation of border points, and to remove discrepancies between the graphic part and the descriptive part of the land and building registry.
Therefore, this study aimed to evaluate the performance of the PM-FAO methodologies for missing data and Hargreaves & Samani (1985) as alternatives to the FAO Penman-Monteith method at different time scales and seasons for the municipalities of Linhares and Sao Mateus, located in the Northern region of the state of Espirito Santo, Brazil.
"With Joyoshare iPhone Data Recovery, people can rescue all kinds of missing data from any data losing disaster; even those from third-party applications on the devices can also be restored."
These single-year models are effective with sparse data and short periods of missing data but fail to use or incorporate all the information available in long term monitoring data sets.
A naive imputation method is the random draw, which imputes missing data with a randomly drawn nonmissing value from the same variable.
In the six centers, 363 patients were retrieved for this observational study, although 61 were excluded due to lost follow-up and another six due to missing data (e.g., no treatment information).
However, this method is generally appropriate only when the chosen dataset contains a very small amount of missing data, for example, 5% missing rate.
Traditional method to handle missing data is discarding those samples with missing values, which is generally called listwise deletion.
Interpolation based methods estimate the missing data according to an average or weighted average of known data which is neighboring the missing data.
But the data have a lot of missing values: 62.2% for phosphate, 59.9% for nitrate, 27.22% for pH, etc., and the size of missing data varies from one-third hour to several months.
Data not available or beyond the first three days of patients' admission were defined as "missing data." BChE (U/L) had categories of <4500 and [greater than or equal to] 4500; age (years) of <30 and [greater than or equal to] 30; WHO stage of I, II, III, and IV; CD4 count (cells/[micro]L) of missing data, <50 and [greater than or equal to] 50; HIV-RNA (copies/mL) of missing data, < [10.sup.5] and [greater than or equal to] [10.sup.5]; hemoglobin (g/L) of missing data, <110 and [greater than or equal to] 110; serum concentration of sodium (mmol/L) of missing data, <130 and [greater than or equal to] 130; and albumin (g/L) of missing data, <35 and [greater than or equal to] 35.
After being asked about the missing data, the spokesman said: "The data that you state is missing is in fact only missing from our website.
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