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NIOSH - National Institute for Occupational Safety and Health

Life Table Analysis System


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Newest LTAS.NET Windows Version 2.0.16 Now Available

The current version, LTAS.NET Version 2.0.16, was released October 2008.  Many of the reference documents have been updated with this release so before you download and begin using this new version please visit the Documentation page to find supporting information, Including

As you prepare to download you will be asked to register so we can send you a notice of updates. Even if you have registered before we ask that you please do so again so we can have current information for you.

While extensive testing on LTAS.NET has been conducted, not all possible variations have been evaluated. If you discover a problem or issue please bring it to our attention at the Contact LTAS Staff page.


Life table analyses originated as a form of survival analysis in which survival times are grouped into intervals. Hazard or incidence rates are calculated for each interval. Intervals might be constructed by age, calendar time, duration of exposure, or level of exposure (for example, ppm). Rates for the cohort under observation might then be compared with external rates for some large (typically unexposed) population to obtain an estimate of the relative survival of the cohort compared with the external population.

The NIOSH Life Table Analysis System was created primarily to analyze cohorts defined by occupational exposures. It therefore requires input of a work history file in addition to a demographic and outcome file. LTAS constructs rates by age, sex, race (usually white/other-race), calendar time, and duration or level of exposure. LTAS then compares the observed rates for the cohort under study with comparison rates from a referent population; rates for several referent populations are supplied with LTAS. Rates are calculated as observed events, typically deaths, divided by person-time at risk in the interval.

The Life Table Analysis System (LTAS) was developed at the National Institute for Occupational Safety and Health (NIOSH) during the 1970s. Originally, LTAS was available only on IBM mainframe computer systems. During the 1990s LTAS was made available in a PC-DOS version called PC-LTAS. The current version of LTAS has been developed for use on the following Windows platforms: 98/2000/NT/XP. This version of LTAS, called LTAS.NET, is more interactive than the previous mainframe or MS-DOS versions and provides greater flexibility for data input, export and analysis.

Page last modified: November 5, 2008
Page last reviewed: October 23, 2008
Content Source: National Institute for Occupational Safety and Health (NIOSH)

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