Errors In Clinical Trials

By Author: Rajesh Kumar
Total Articles: 17
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Below is the list of 12 most common errors committed during the clinical trials.


1) Systematic Error:

In an analytical study, a systematic error can occur in the induction of study subjects, the assignment to treatment groups, in the harvest data and in analyzing, interpreting, publication and revision of data.


2) Berkson Error:

It is a kind of selection error which may occur in case-control studies, in which being sick and exposed to the risk factor of increasing the likelihood of being hospitalized, which gives rise to an exposure rate consistently higher among the hospitalized cases compared with controls. There is a list of assays in clinical research that should be review to avoid such errors.


3) Error by Investigator:

This is a systematic error or a variation of the error information due to the selective collection of data consciously or unconsciously by the investigator to limit the uses of structured ...
... questionnaires.


4) Error Information:

It is a systematic error resulting from the measurement of exposure (case studies and controls) or evolution (cohort studies and clinical trials) with different intensity between the two compared groups. This error is the most common error which is committed by a contract research organization during their medical writing or the clinical data management services.


5) Memory Error:

It is a systematic error due to differences in the memory of facts or previous experience.

In case studies and controls, it is possible that more cases remember that controls some of the previous experiments, which normally leads to an overestimation of the benefits due (NRS).

The awareness of memory error is a variant of the memory error, in which the memory of the two patient groups was not aware in the same way, the interview with structured questionnaire helps to limit it.


6) Observation Error:

It is the systematic difference between the actual and the saved value. In a clinical study, this is more common, it is due to the knowledge, the observer and the treatment received by each subject.


7) Error of Issuance:

It is a form of selection error resulting to believe that the studies published are those actually incurred.

Many clinical trials are not published (because they do not finish, because the researcher considers insignificant results, because the developer does not want it or because they are not accepted for publication). This happens especially with trials that did not register differences between treatment groups.
Further trials are published in more than one medical journal (duplicate publication), they are sometimes signed by different authors, so it becomes difficult to identify some of the duplicate publications.

The two phenomena tend to determine the Meta-analyzes that include only the results of clinical trials published in general overestimate the effect of experimental treatment.


8) Selection Error:

This is a systematic error due to the fact that the characteristics of subjects enrolled in a study are different patient characteristics that are not included, so that the sample is not representative of the reference population.


9) Error Type 1:

This is an error of rejecting a null hypothesis if it is true. The alpha error is the error that is committed when a null hypothesis is rejected when it is true. The alpha probability is the probability of committing a Type I error. It is customary to fix a = 0.05, that is to say a 5% probability.


10) Type 2 of Error:

This is a mistake of accepting a null hypothesis if it is false. The beta error is the error that is committed if a person does not reject the null hypothesis when it is false. The beta probability is the probability of committing a Type II error. It is the custom of using a 10% (so that 1 - β = 0.90 ) or 20% (so 1 - for β = 0.80 ). The term 1 - β is the statistical power of the study.


11) Type 3 of Error:

This is a mistake of regarding the higher efficacy of treatment whereas in reality it is less.


12) Alpha Global Error:

This is the error in which alpha is committed to make multiple comparisons.