TRIM (software)
| TRIM | |
|---|---|
| Basic data
|
|
| Maintainer | J. Pannekoek and A. van Strien |
| developer | Statistics Netherlands |
| Current version |
3.53 ( November 8, 2006 ) |
| operating system | Windows 32-bit systems |
| category | statistics |
| TRIM at cbs.nl | |
TRIM ( TR ends & I ndices for M onitoring data ) is at Statistics Netherlands developed Freeware - A computer program for time series analysis of monitoring data from animal and plant life . It evaluates the counting data using a Poisson regression and provides trend estimates of the population numbers and annual abundance indices.
Application area
Monitoring programs for flora and fauna normally consist of the annual determination of the number of individuals of all or selected species on a large number of monitoring areas. The main purpose of such monitoring activities is to determine changes in population size or geographic distribution over the years. Such changes are often represented in the form of indices, taking the first year as the base and setting its index to 1 or 100. Monitoring data usually have "annoying" statistical properties that complicate their analysis:
- They often have incorrect values, i. H. not all areas were examined in all years.
- The data are autocorrelated in time, i.e. H. the population size of a species in an area depends on the population size in previous years, so the independence requirement is violated.
- The data show overdispersion ( English over dispersion ) d. H. the variance is greater than the expected value , so an important property of the Poisson distribution is not fulfilled.
- The trends show breakpoints over the years.
- Species show different trends depending on habitat types or other covariates.
- Different habitat types are investigated with different degrees of intensity, which makes it difficult to estimate a national (or Europe-wide) abundance trend.
Solutions for all these problems are implemented in TRIM and can be selected via the menu. TRIM can be downloaded from the Statistics Netherlands website. Since 2018, TRIM has also been available as an R package.
distribution
TRIM has been used for more than ten years in the evaluation of nationwide monitoring data in the Netherlands ( e.g. by Sovon Vogelonderzoek Nederland ) and provides the official results on the state of fauna and flora published by Statistics Netherlands. In addition, TRIM is also used internationally, for example by the European Bird Census Council and the monitoring of birds of prey and owls in Europe.
literature
- A. van Strien, J. Pannekoek, W. Hagemeijer, T. Verstrael: A loglinear Poisson regression method to analyze bird monitoring data . In: A. Anselin (Ed.) Bird Numbers 1995, Proceedings of the International Conference and 13th meeting of the European Bird Census Council. Bird Census News. Volume 13, 2000, pp. 33-39.
- J. Pannekoek, A. van Strien: TRIM 3 Manual. Statistics Netherlands, Voorburg, 2005. online
Individual evidence
- ↑ https://cran.r-project.org/web/packages/rtrim/index.html
- ↑ Archived copy ( memento of the original from July 13, 2012 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
