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OHI Science | Citation policy

Global OHI assessments require synthesizing highly heterogeneous information that is freely available from nearly one hundred sources. Data from each source are prepared and modeled using freely available coding and version control software. You may freely download and use any data, code, or instructional guides, but please see our Citation Policy.

With each annual global assessment we have incrementally improved data processing and modeling methods based on new information, knowledge, and feedback. Thus, for annual scores to be comparable with previous years, we recalculate previous assessments with the most recent methods for each past assessment year. All code and most data are available online on GitHub.

Global assessment scores 2012-2020

Quick access to .csv files of calculated global scores.

Documentation and Instruction

Full methods and data

Final scores and methods are released annually each fall. Ongoing work is available in our OHI-Science GitHub repositories. A description of file organization is available.


We thank all the groups that collect and share data openly; please see the global layers page for a full list. We also thank developers and communities that make and teach free software tools, in particular R, RStudio, git, GitHub, and rOpenSci.

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