Life Table Analysis System
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Major Changes in LTAS.NET Version 4.0
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Changes affecting software usability
- Replaced SQL Server Express 2005 used in all LTAS.NET 3.0 versions with the 2014 version of SQL Server Express for better Windows compatibility and security.
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Support for Windows 7 SP1/8/8.1/10 64-bit
- LTAS.NET 4.0 may be installed on computers with Windows 7 SP1, 8, 8.1, or 10 64-bit operating system.
- Changed extension of project files from .ltas3 to .ltas4 to better facilitate upgrading from LTAS 3.0.
- When opening a project in LTAS.NET 4.0, user can open and convert projects created in the previous version (3.0 or 2.0) of LTAS.NET in the dropdown menu.
- Users may operate LTAS.NET 3.0 and 4.0 side-by-side if they have Windows 7 SP1/8/8.1/10 64-bit, although we recommend uninstalling LTAS.NET 3.0 as soon as feasible, because Microsoft will not provide security updates for its software platform (SQL Server Express 2005) beyond April 12, 2016.
- The 32-bit version of Windows 7/8/8.1/10 is not supported.
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Changes affecting software functionality (Please refer to Appendix C in the user’s manual for variable ID description)
- Corrected data requirement logic to reject History file records with partial Start or End dates (EC20r) and Person file records with partial Risk Begin dates (PC140r).
- Corrected data requirement logic to reject persons with no person time (ST40r) so persons with 1 day of person time are not rejected.
- Updated data requirement PC100w to PC100x to reject persons with date last observed prior to the rate file begin date (action changed from warning to exclusion).
- Corrected documentation of rule PR20r from “DLO > Risk begin” to “DLO >= Risk begin”.
- Corrected implementation of rule OC24r to exclude diagnoses when identifying the “earliest” outcome date and updated documentation.
- Corrected a problem that caused LTAS to terminate completely instead of rejecting a person with an invalid risk begin date (PC140r).
- Corrected a problem that prevented the requirement of a person having 1 or more histories in the study period (EP40r) from being enforced.
- Updated actions to support non-terminal analyses:
- M50r now rejects any outcome (terminal or non-terminal) that is after the person’s DLO and rejects both the outcome and the person if the terminal outcome date is before the person’s DLO (this latter requirement was not previously enforced resulting in a person with an obvious error in their data (death date prior to DLO) erroneously contributing person-years at risk in a terminal study).
- OC23r now rejects both the outcome and the person if the outcome date is not in the rate file (previously, in non-terminal studies, an outcome prior to the rate file begin date would have been rejected, but the person was not, erroneously allowing the person to contribute person-years at risk).
- The requirement that a person’s outcome date be greater than or equal to their risk begin date (M60r) is now enforced (both the person and the outcome are rejected when the outcome date is prior to the risk begin date).
- Updated M20r to only reject history records that begin prior to the person’s date of birth (previously M20r would reject history records that began on or prior to the subject’s date of birth).
- Corrected Post-Stratify Personal Cumulative Dose report for unlagged cumulative level variables for cases who continued to work after their diagnosis date in non-terminal analyses.
- Corrected a problem with the p-values reported in the Standardized Mortality Ratio (SMR) analysis. If ‘Report p-values instead of CI’ under ‘Confidence Interval or p-value’ in ‘Report Options’ was selected, the p-values would be reported incorrectly when the approximation formula was used (i.e., observed deaths greater than 20) and SMR<1 (i.e., Observed (D) less than the Expected (E)). All p-values are now correctly reported in LTAS 4.0.
- Disabled time since first or last employment (TSFE/TSLE) in the horizontal variable dropdown menu in SRR analysis. This function is disabled due to a potential issue (“sparse data bias”) not related to LTAS algorithm.
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Changes to improve reports and data export capabilities
- Added a missing report file that prevented SMR list reports with p-values from being generated.
- Added the rule ID to the import exceptions and stratify rejects reports.
- Changed the category order for an accumulating variable to be sorted by the cutpoint rather than by the label in Analyze reports.
- Added the lag for employment status in the Analyze report when using a lag for employment status (Active vs. Inactive).
- Added an option to report Person Days instead of Person Years to the Distribution of Person Years report.
- Included strata that do not have rates in the cohort export.
- Added a warning to all SRR reports “Warning: Presence of large imbalances in person-year distribution across categories can lead to biased SRR”.
Major Changes in LTAS.NET version 3.0
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Support for Windows Vista and Windows 7
- LTAS.NET 3.0 may be installed on Windows 7, Vista, or XP (note that if your operating system is Windows 98, NT, 2000, or earlier versions of Windows, LTAS. NET 3.0 will not work).
- Changed extension of project files from .ltas to .ltas3 to better facilitate upgrading from LTAS 2.0.
- When opening a project in LTAS.NET 3.0, user is prompted to open and convert projects created in the previous version of LTAS.NET.
- LTAS.NET 3.0 will also work on Windows XP side-by-side with LTAS.NET 2.0.
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New rate file structure
- The cause map and the rate file have been merged into a single file, which simplifies the importing of rates.
- Rate files are easier to manage: they can be deleted from the default folder if no longer needed (this reduces the “clutter” in the rate pull-down box).
- Updated US underlying and multiple-cause rates and proportions (for both 92- and 119-cause files) through 2007.
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Changes affecting software functionality
- Support for reporting p-values in SRR and SMR reports.
- Changed the ordering of fields in the Import Wizard drop-down menu used to map fields so that they are ordered more logically (e.g., ID, sex, race, vital status, DOB, person-year begin date, date last observed, and any user-specified variables in the order entered), instead of alphabetically.
- Changed the ordering of fields in the Import Options report so that they are ordered by column position (instead of alphabetically).
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Changes affecting software usability
- Updated Report Viewer to use SQL Server Reports, resulting in better export capabilities.
- Updated Database Engine to use SQL Server 2005, doubling the storage capacity from 2GB to 4GB.
- User documentation is now section 508 compliant.
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Changes to improve reports and data export capabilities
- Inclusion of Supermajor (“All Causes” and “All Cancers”) and Major cause-of-death categories in cohort export file.
- Added a new capability in Stratify, allowing user to report or export the Post-Stratify Personal Cumulative Dose for each subject, which will give lagged cumulative exposures.
- Changed analysis reports so that exposure lag information is included with the page variables.
- Page last reviewed: October 17, 2013
- Page last updated: December 31, 2015
- Content source:
- National Institute for Occupational Safety and Health Division of Surveillance, Hazard Evaluations and Field Studies