Time-stamp recording

In this case time stamped recordings of input data will be required so that synchronisation of input data with process execution, which must also be recorded, can be achieved during analysis of the test results. For example if we are looking for evidence that a particular branch, which is dependent on a value of an input, was executed we would need to confirm that the input conditions for the branch were achieved if they were not, due to the necessary signal being applied after the conditional statement being executed for example, it would be futile to search for the evidence. 

Computer systems must provide time-stamped audit trails to record actions that create, modify, or delete electronic records. 

In postmarketing electronic longitudinal medical records, redundant and potentially contradictory information may come from several sources, (e.g., reports from medical residents, their supervisors, the attending physicians). In these cases time stamping of each event may help to delineate the important sequences in understanding the adverse events. 

A few days later, the infantry colonel s scoring of the military tasks arrived in the mail. He had been required to rate them blind, because there were deliberately no time stamps on them and Lloyd had re-recorded them in random sequence. Nevertheless, the colonel s judgment of military competence in each scene conformed closely to the corresponding NF score. The Edgewood cognitive tests once again proved to be good predictors of performance in the field. 

Paper subject diaries are notoriously poor in their legibility, completeness and accuracy. Electronic diaries are small, portable devices that can present text and graphics to the subject. They allow the subject to record and store responses, which can be time-stamped for each entry made. 

Written procedures and practices must be in place within the laboratory to verify the accuracy of manually entered and electronically transferred data collected on automated systems. The primary documentation for data entry requirements is an audit trail. Laboratories must ensure that an audit trail exists and is maintained. This audit trail must indicate date and time stamps for each record transmitted and the source instrument for each entry. 

Fig. 15.9. Tracking usage of PGVL Hub. Each time a user logins into PGVL Hub, information about user ID and time stamp is recorded into a tracking database. A usage report can be generated via a Web reporting tool.

The use of time-stamped audit trails (Part 11.10(c) and (e)) to record changes, to record all write-to-file operations, and to independently record the date and time of any network system administrator actions or data entries/changes. 

Audit trails refer to a journal that records modifications to electronic records. The persons or automated processes operating on the user s behalf may perform these modifications. The audit-trail mechanism provides the capability to reconstruct the data prior to a modification, and therefore must not obscure the previously recorded data. The tracking mechanism must include a computer-generated time stamp that indicates the time of the entry. Audit trails are computer generated and can be part of the record that has been modified or a standalone record linked to the modified record. 

An audit trail is a journal recording any modifications carried out by the users, or by the processes operating on behalf of the user, to the electronic records. This mechanism provides the capability to reconstruct modified data and must not obscure the previously entered data. The tracking mechanism includes adding computer-generated date and time stamps to the record, to indicate when the record was modified, the types of modifications performed, and the identity of the person performing the modification to the record. 

The scanner is designed to recognise coincidences where events occur in two opposing buckets within a resolving time of 12 ns. In normal operation, only coincidences between two elements in the same ring or adjacent rings (of the 8) were accepted, but for PEPT use this restriction was removed. The data acquisition system of the scanner was also modified so that coincidence data is recorded in list mode with time stamps at 1 ms intervals. 

Fig. 30. Schematic design of a simple but very useful and efficient data reduction algorithm. Data representing the time trajectory of an individual variable are only kept (= recorded, stored) when the value leaves a permissive window which is centered around the last stored value. If this happens, the new value is appended to the data matrix and the window is re-centered around this value. This creates a two-column matrix for each individual variable with the typical time stamps in the first column and the measured (or calculated) values in the second column. In addition, the window width must be stored since it is typical for an individual variable. This algorithm assures that no storage space is wasted whenever the variable behaves as a parameter (i.e. does not change significantly with time, is almost constant) but also assures that any rapid and/or singular dynamic behavior is fully documented. No important information is then lost...

The electronic record system lacks computer generated time stamped audit trails. [FDA Warning Letter, 2000]... 

There is no assurance that the XXXXXX could create an audit trail that was computer generated and time stamped to independently record the date and time of operator entries and actions as required by 21 CFR 11.10(e). [FDA Warning Letter, 1999]... 

There must be a system-generated time-stamped audit trail, created independently of the operator of a system, for any access to, modification of, or deletion of records or the audit trail itself. This audit trail is intended to enable detection of record and signature falsifications and to provide an evidentiary trail in the event of falsification. (Preamble Comments 72-74)... 

User-independent computer-generated time-stamped audit trails. Procedures should be available to use secure, computer-generated, time-stamped audit trails to independently record the date and time of operator entries and actions that create, modify, or delete electronic records. Record changes shall not obscure previously recorded information. Such audit trail documentation shall be retained for a period at least as long as that required for the subject electronic records and shall be available for agency review and copying. 

Paper subject diaries are notoriously poor in their legibility, completeness and accuracy. Electronic diaries are small, portable de vices that can present text and graphics to the subject. They allow the subject to record and store responses, which can be time-stamped for each entry made. The data can then be downloaded directly into the clinical trial database. The main drawbacks include the need for training of the subject in the diary s use, possible errors in local time settings and the logistics of distribution, maintenance and recovery of the diaries. 

Authentication is usually performed by entering a unique user identification (ID) and password. If data are transferred automatically from external software, the source system either must provide a similar mechanism to identify a valid user or the external system has to log on to the record manager with a unique identifier. In any case, data that are entering a compliant-ready record manager require this identification. The authentication needs to be logged with a date and time stamp in an audit trail. The same requirement applies to the modification of data that already exist in the record, if the user is not already in an authenticated session. In fully regulated environments, a reason for the modification has to be supplied before changes can be made. 

Classical medical records have material not in any particular order, except for date and maybe time, in which case it is said to be time-stamped. Normally, however, e.g., one would create a separate entry such as PHSx resting pulse time=08/03/2004 11 46 00 or even PHSx resting pulse =time =08/03/2004 11 46 00 to go alongside PHSx resting pulse =time =70, and similarly for other items, so allowing time series analysis (effectively correlations between time of observation and the observed value).To do this requires conversion to some universal leap-year-free decimal time such as 2009.98666, which is some moment of December 2009 (there are also things called leap-seconds to take into account). 

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