Trends and Indices for Monitoring Data

The TRIM model is widely used for estimating growth and decline of animal populations based on (possibly sparsely available) count data. The current package is a reimplementation of the original TRIM software developed at Statistics Netherlands by Jeroen Pannekoek. See <> for more information about TRIM.


version 2.0.6

  • Removed spurious output from index() function
  • Fixed bug in totals() which prevented both obs=TRUE and level!=NULL

version 2.0.5

  • Fixed bug causing non-zero standard errors for the base year index if this isn't the first year (thanks to Tomas Telensky)

version 2.0

  • Many major updates (monthly data; stratified trim; advanced visualizations); See the vignette "trim 2 extensions".

version 1.3.1

  • Fixed bug concerning covariates
  • Fixed typos and minor edits in vignettes (thanks to Martin Poot)

version 1.3.0

  • Integration of experimental monthly version

version 1.2.0

  • Introduced time-window-based indexing
  • Automatically converts non-factor covariates to factors
  • Fixes a bug occuring when empty sites are combined with covariates (thanks to Marnix de Zeeuw)
  • Speed improvements
  • Minor bug fixes

version 1.1.5

  • Now generates an error when the computed overdispersion is 0, and a warning when overdispersion < 1 (thanks to Oscar Ramírez for proving a data set where this happened)

version 1.1.4

  • Fixed a bug caused by auto-removal of empty factorial sites (thanks to Tomás Murray)

version 1.1.3

  • Fixed a bug resulting in wrong p-values output by the overall() function (thanks to Anna Marie Holand for reporting).

version 1.1.2

  • Fixed problem when to many years have no or 0 counts, such that the expected value becomes effectively 0 as well. This case now generates an error message “Zero expected value” (thanks to Arco van Strien for proving this case)

version 1.1.1

  • Fixed problem during stepwise regression when the algorithm wants to remove the first changepoint (thanks to Asaf Tsoar)
  • Fixed computation of standard errors when model==1 (thanks to Asaf Tsoar)

version 1.1.0

  • Added backward compatibility option in overall() to match erroneous overall trend interpretation in original TRIM (thans for Lars Petterson to pointing out the differences in trend interpretation)

version 1.0.2

  • Limit on regression parameters now equal to original TRIM (thanks to Lars Petterson)

version 1.0.1

  • initial CRAN release

Reference manual

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2.1.1 by Patrick Bogaart, 2 years ago

Report a bug at

Browse source code at

Authors: Patrick Bogaart [aut, cre] , Mark van der Loo [aut] , Jeroen Pannekoek [aut]

Documentation:   PDF Manual  

EUPL license

Imports methods, utils, stats, graphics, grDevices

Suggests testthat, knitr, rmarkdown, R.rsp

See at CRAN