Last updated: 2023-12-15

SDG indicator metadata(Harmonized metadata template - format version 1.1)

0. Indicator information (SDG_INDICATOR_INFO)
0.a. Goal (SDG_GOAL)
Goal 15: Protect, restore and promote sustainable use of terrestrial ecosystems, sustainably manage
forests, combat desertification, and halt and reverse land degradation and halt biodiversity loss

0.b. Target (SDG_TARGET)
Target 15.5: Take urgent and significant action to reduce the degradation of natural habitats, halt the lossof biodiversity and, by 2020, protect and prevent the extinction of threatened species

0.c. Indicator (SDG_INDICATOR)
Indicator 15.5.1: Red List Index

0.d. Series (SDG_SERIES_DESCR)
ER_RSK_LST - Red List Index [15.5.1]

0.e. Metadata update (META_LAST_UPDATE)
2023-12-15

0.f. Related indicators (SDG_RELATED_INDICATORS)Disaggregations of the Red List Index are also of particular relevance as indicators towards the following
SDG targets (Brooks et al. 2015): SDG 2.4 Red List Index (species used for food and medicine); SDG 2.5
Red List Index (wild relatives and local breeds); SDG 12.2 Red List Index (impacts of utilisation) (Butchart2008); SDG 12.4 Red List Index (impacts of pollution); SDG 13.1 Red List Index (impacts of climatechange); SDG 14.1 Red List Index (impacts of pollution on marine species); SDG 14.2 Red List Index(marine species); SDG 14.3 Red List Index (reef-building coral species) (Carpenter et al. 2008); SDG 14.4
Red List Index (impacts of utilisation on marine species); SDG 15.1 Red List Index (terrestrial & freshwater
species); SDG 15.2 Red List Index (forest-specialist species); SDG 15.4 Red List Index (mountain species);
SDG 15.7 Red List Index (impacts of utilisation) (Butchart 2008); and SDG 15.8 Red List Index (impacts ofinvasive alien species) (Butchart 2008, McGeoch et al. 2010).

0.g. International organisations(s) responsible for global monitoring(SDG_CUSTODIAN_AGENCIES)

International Union for Conservation of Nature (IUCN)

1. Data reporter (CONTACT)
1.a. Organisation (CONTACT_ORGANISATION)
International Union for Conservation of Nature (IUCN)
BirdLife International (BLI)

2. Definition, concepts, and classifications (IND_DEF_CON_CLASS)
2.a. Definition and concepts (STAT_CONC_DEF)
Definition:

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The Red List Index measures change in aggregate extinction risk across groups of species. It is based on
genuine changes in the number of species in each category of extinction risk on The IUCN Red List of
Threatened Species (www.iucnredlist.org) is expressed as changes in an index ranging from 0 to 1.
Concepts:
Threatened species are those listed on The IUCN Red List of Threatened Species in the categories
Vulnerable, Endangered, or Critically Endangered (i.e., species that are facing a high, very high, or
extremely high risk of extinction in the wild in the medium-term future). Changes over time in the
proportion of species threatened with extinction are largely driven by improvements in knowledge andchanging taxonomy. The indicator excludes such changes to yield a more informative indicator than thesimple proportion of threatened species. It therefore measures change in aggregate extinction risk acrossgroups of species over time, resulting from genuine improvements or deteriorations in the status ofindividual species. It can be calculated for any representative set of species that have been assessed for
The IUCN Red List of Threatened Species at least twice (Butchart et al. 2004, 2005, 2007). To calculate the
Red List Index for individual countries and regions, each species contributing to the index is weighted by
the proportion of its global range within the particular country or region. The resulting index therefore
shows the aggregate extinction risk for species within the country or region relative to its potential
contribution to global species extinction risk (within the taxonomic groups included).

2.b. Unit of measure (UNIT_MEASURE)
Index.
The Red List Index for a particular country or region is an index of the aggregate extinction risk for species
within the country or region relative to its potential contribution to global species extinction risk (within
the taxonomic groups included).
It is measured on a scale of 0 to 1, where 1 is the maximum contribution that the country or region canmake to global species survival, equating to all species being classified as Least Concern on the IUCN Red
List, and 0 is the minimum contribution that the country or region can make to global species survival,
equating to all species in the country or region having gone extinct.

2.c. Classifications (CLASS_SYSTEM)The Red List Index is based on categorisations of species on the IUCN Red List of Threatened Species(www.iucnredlist.org), defined following IUCN (2012a).

3. Data source type and data collection method (SRC_TYPE_COLL_METHOD)
3.a. Data sources (SOURCE_TYPE)
The Red List Index is based on data from The IUCN Red List of Threatened Species (www.iucnredlist.org),
in particular the numbers of species in each Red List category of extinction risk, and changes in thesenumbers over time resulting from genuine improvements or deteriorations in the status of species. Dataon species’ distribution, population size, trends and other parameters that underpin Red List assessments
are gathered from published and unpublished sources, species experts, scientists, and conservationists
through correspondence, workshops, and electronic fora.

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3.b. Data collection method (COLL_METHOD)
A detailed description of the Red List Assessment process is provided athttps://www.iucnredlist.org/assessment/process. See also information under other categories.

3.c. Data collection calendar (FREQ_COLL)
The IUCN Red List of Threatened Species is updated at least three times per year. Red List Indices for setsof species that have been comprehensively reassessed are usually released alongside the relevant updateof the IUCN Red List. Data are stored and managed in the Species Information Service database, and aremade freely available for non-commercial use through the IUCN Red List website (www.iucnredlist.org).
Re-assessments of extinction risk are required for every species assessed on The IUCN Red List of
Threatened Species once every ten years, and ideally undertaken once every five years. A Red List
Strategic Plan details a calendar of upcoming re-assessments for each taxonomic group.

3.d. Data release calendar (REL_CAL_POLICY)
The Red List Index is updated annually in November-December using the latest data from reassessmentson the IUCN Red List.

3.e. Data providers (DATA_SOURCE)
National agencies producing relevant data include government, non-governmental organisations (NGOs),and academic institutions working jointly and separately. Data are gathered from published andunpublished sources, species experts, scientists, and conservationists through correspondence,
workshops, and electronic fora. Data are submitted by national agencies to IUCN, or are gathered
through initiatives of the Red List Partnership. The members of the Red List Partnership are listed athttps://www.iucnredlist.org/about/partners, and currently include: ABQ BioPark; Arizona State University
Centre for Biodiversity Outcomes; BirdLife International; Botanic Gardens Conservation International;
Conservation International; Global Wildlife Conservation; Missouri Botanical Garden; NatureServe; Royal
Botanic Gardens, Kew; Sapienza University of Rome; Texas A&M University; and Zoological Society of
London.

3.f. Data compilers (COMPILING_ORG)
Name:International Union for Conservation of Nature (IUCN)
Description:
Compilation and reporting of the Red List Index at the global level is conducted by the International
Union for Conservation of Nature (IUCN) and BirdLife International, on behalf of the Red List Partnership.

3.g. Institutional mandate (INST_MANDATE)
Responsibility for overseeing Red List assessments, which underpin the Red List Index, is assigned to
Red List Authorities according to the IUCN Red List Rules of Procedure(https://nc.iucnredlist.org/redlist/content/attachment_files/Rules_of_Procedure_for_IUCN_Red_List_20
17-2020.pdf). The role of Red List Authorities is to ensure that all species within their remit are correctly

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assessed against the IUCN Red List Categories and Criteria at least once every ten years and, if possible,
every five years. Further details of the roles and responsibilities of Red List Authorities are provided athttps://www.iucnredlist.org/assessment/authorities, and the full list and contact details for all appointed
Red List Authorities are available at https://www.iucn.org/commissions/ssc-groups.

4. Other methodological considerations (OTHER_METHOD)
4.a. Rationale (RATIONALE)
The world’s species are impacted by a number of threatening processes, including habitat destruction
and degradation, overexploitation, invasive alien species, human disturbance, pollution and climatechange. This indicator can be used to assess overall changes in the extinction risk of groups of species as aresult of these threats and the extent to which threats are being mitigated.
The Red List Index value ranges from 1 (all species are categorized as ‘Least Concern’) to 0 (all species are
categorized as ‘Extinct’), and so indicates how far the set of species has moved overall towards
extinction. Thus, the global Red List Index allows comparisons between sets of species in both theiroverall level of extinction risk (i.e., how threatened they are on average), and in the rate at which this riskchanges over time. A downward trend in the global Red List Index over time means that the expected
rate of future species extinctions is worsening (i.e., the rate of biodiversity loss is increasing). An upward
trend means that the expected rate of species extinctions is abating (i.e., the rate of biodiversity loss isdecreasing), and a horizontal line means that the expected rate of species extinctions is remaining thesame, although in each of these cases it does not mean that biodiversity loss has stopped. An upward
global Red List Index trend would indicate that the SDG Target 15.5 of reducing the degradation ofnatural habitats and protecting threatened species is on track. A global Red List Index value of 1 would
indicate that biodiversity loss has been halted.
The name “Red List Index” should not be taken to imply that the indicator is produced as a composite
indicator of a number of disparate metrics (in the same way that, e.g., the Multidimensional Poverty
Index is compiled). The Red List Index provides an indicator of trends in species’ extinction risk, asmeasured using the IUCN Red List Categories and Criteria (Mace et al. 2008, IUCN 2012a), and is compiled
from data on changes over time in the Red List Category for each species, excluding any changes driven
by improved knowledge or revised taxonomy.
The Red List Index was used as an indicator towards the 2011–2020 Strategic Plan for Biodiversity (CBD
2014, Tittensor et al. 2014, CBD 2020a), the Convention on Biological Diversity’s 2010 Target (Butchart etal. 2010) and Millennium Development Goal 7. It has been proposed as a Headline Indicator in the draft
post-2020 Global Biodiversity Framework (CBD 2020b).

4.b. Comment and limitations (REC_USE_LIM)
There are four main sources of uncertainty associated with Red List Index values and trends.
a. Inadequate, incomplete or inaccurate knowledge of a species’ status. This uncertainty is minimized
by assigning estimates of extinction risk to categories that are broad in magnitude and timing.

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b. Delays in knowledge about a species becoming available for assessment. Such delays apply to asmall (and diminishing) proportion of status changes, and can be overcome in the Red List Index
through back-casting (Butchart et al. 2007).
c.

Inconsistency between species assessments. These can be minimized by the requirement toprovide supporting documentation detailing the best available data, with justifications, sources,and estimates of uncertainty and data quality, which are checked and standardized by IUCN
through Red List Authorities, a Red List Technical Working Group and an independent Standards
and Petitions Sub-committee. Further, detailed Guidelines on the Application of the Categories
and Criteria are maintained (IUCN SPSC 2019), as is an online training course (in English, Spanish
and French).

d. Species that are too poorly known for the Red List Criteria to be applied are assigned to the Data
Deficient category. For birds, only 0.8% of extant species are evaluated as Data Deficient,compared with 24% of amphibians. If Data Deficient species differ in the rate at which their
extinction risk is changing, the Red List Index may give a biased picture of the changing extinction
risk of the overall set of species. The degree of uncertainty this introduces is estimated through abootstrapping procedure that randomly assigns each Data Deficient species a category based on
the numbers of non-Data Deficient species in each Red List category for the set of species underconsideration, and repeats this for 1,000 iterations, plotting the 2.5 and 97.5 percentiles as lower
and upper confidence intervals for the median.
The main limitation of the Red List Index is related to the fact that the Red List Categories are relatively
broad measures of status, and thus the Red List Index for any individual taxonomic group can practicallybe updated at intervals of at least four years. However, as the overall index is aggregated across multiple
taxonomic groups, with groups reassessed asynchronously, it can be updated annually. A further
limitation is that the Red List Index does not reflect particularly well the deteriorating status of common
species that remain abundant and widespread but are declining slowly.

4.c. Method of computation (DATA_COMP)The Red List Index is calculated at a point in time by first multiplying the number of species in each Red
List Category by a weight (ranging from 1 for ‘Near Threatened’ to 5 for ‘Extinct’ and ‘Extinct in the Wild’)and summing these values. This is then divided by a maximum threat score, which is the total number of
species multiplied by the weight assigned to the ‘Extinct’ category. This final value is subtracted from 1 togive the Red List Index value.
Mathematically this calculation is expressed as:
𝑅𝐿𝐼𝑡 = 1 −𝛴𝑠 𝑊𝑐(𝑡,𝑠)(𝑊𝐸𝑋 ∗ 𝑁)

Where Wc(t,s) is the weight for category (c) at time (t) for species (s) (the weight for ‘CriticallyEndangered’ = 4, ‘Endangered’ = 3, ‘Vulnerable’ = 2, ‘Near Threatened’ = 1, ‘Least Concern’ = 0. ‘CriticallyEndangered’ species tagged as ‘Possibly Extinct’ or ‘Possibly Extinct in the Wild’ are assigned a weight of5); WEX = 5, the weight assigned to ‘Extinct’ or ‘Extinct in the Wild’ species; and N is the total number ofLast updated: 2023-12-15

assessed species, excluding those assessed as Data Deficient in the current time period, and thoseconsidered to be ‘Extinct’ in the year the set of species was first assessed.
The formula requires that:• Exactly the same set of species is included in all time periods, and• The only Red List Category changes are those resulting from genuine improvement or
deterioration in status (i.e., excluding changes resulting from improved knowledge or taxonomic
revisions), and• Data Deficient species are excluded (or treated according to the procedure described above).
In many cases, species lists will change slightly from one assessment to the next (e.g., owing to taxonomic
revisions). The conditions can therefore be met by retrospectively adjusting earlier Red List
categorizations using current information and taxonomy. This is achieved by assuming that the current
Red List Categories for the taxa have applied since the set of species was first assessed for the Red List,
unless there is information to the contrary that genuine status changes have occurred. Such information
is often contextual (e.g., relating to the known history of habitat loss within the range of the species). If
there is insufficient information available for a newly added species, it is not incorporated into the Red
List Index until it is assessed for a second time, at which point earlier assessments are retrospectively
corrected by extrapolating recent trends in population, range, habitat and threats, supported byadditional information. To avoid spurious results from biased selection of species, Red List Indices are
typically calculated only for taxonomic groups in which all species worldwide have been assessed for the
Red List, or for samples of species that have been systematically or randomly selected.
The methods and scientific basis for the Red List Index were described by Butchart et al. (2004, 2005,
2007, 2010).
Butchart et al. (2010) also described the methods by which Red List Indices for different taxonomic
groups are aggregated to produce a single multi-taxon Red List Index. Specifically, aggregated Red List
Indices are calculated as the arithmetic mean of modelled Red List Indices. Red List Indices for eachtaxonomic group are interpolated linearly for years between data points and extrapolated linearly (with aslope equal to that between the two closest assessed points) to align them with years for which Red List
Indices for other taxa are available. The Red List Indices for each taxonomic group for each year aremodelled to take into account various sources of uncertainty:i)Data Deficiency: Red List categories (from Least Concern to Extinct) are assigned to all Data
Deficient species, with a probability proportional to the number of species in non-Data Deficient
categories for that taxonomic group;ii) Extrapolation uncertainty: although RLIs were extrapolated linearly based on the slope of theclosest two assessed point, there is uncertainty about how accurate this slope may be. To
incorporate this uncertainty, rather than extrapolating deterministically, the slope used forextrapolation is selected from a normal distribution with a probability equal to the slope of theclosest two assessed points, and standard deviation equal to 60% of this slope (i.e., the CV is 60%);iii) Temporal variability: the ‘true’ Red List Index likely changes from year to year, but because
assessments are repeated only at multi-year intervals, the precise value for any particular year is
uncertain.

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To make this uncertainty explicit, the Red List Index value for a given taxonomic group in a given year is
assigned from a moving window of five years, centred on the focal year (with the window set as 3-4 years
for the first two and last two years in the series). Note that assessment uncertainty cannot yet beincorporated into the index. Practically, these uncertainties are incorporated into the aggregated Red List
Indices as follows: Data Deficient species were allotted a category as described above, and a Red List
Index for each taxonomic group was calculated interpolating and extrapolating as described above. A
final Red List Index value was assigned to each taxonomic group for each year from a window of years as
described above. Each such ‘run’ produced a Red List Index for the complete time period for eachtaxonomic group, incorporating the various sources of uncertainty. Ten thousand such runs are
generated for each taxonomic group, and the mean is calculated.
Methods for generating national disaggregations of the Red List Index are described below in section 5 on
Data availability and disaggregation.

4.d. Validation (DATA_VALIDATION)
Red List Assessments are checked before submission to IUCN by Assessors and Red List Authority
Coordinators, to ensure that all of the required supporting information is provided in the appropriate
format, distribution maps follow the required mapping standards(https://www.iucnredlist.org/resources/mappingstandards), and the IUCN Red List Criteria have been
applied appropriately and consistently following IUCN Guidelines (IUCN SPSC 2019). For further details,
see https://www.iucnredlist.org/assessment/process. All submitted assessments must be reviewed by atleast one Reviewer designated by the Red List Authority. For more details on the review process, see theRules of Procedure(https://nc.iucnredlist.org/redlist/content/attachment_files/Rules_of_Procedure_for_IUCN_Red_List_20
17-2020.pdf).
When Red List Indices are updated each year, the updated index (and underlying numbers of species ineach Red List Category) are made available for review by countries prior to submission to the SDG
Indicators Database. This is achieved through updating the country profiles in the Integrated Biodiversity
Assessment Tool (https://ibat-alliance.org/country_profiles) and circulating these for consultation andreview to CBD National Focal Points, SDG National Statistical Office Focal Points, and IUCN State
Members.

4.e. Adjustments (ADJUSTMENT)No adjustments are made to the index with respect to harmonization of breakdowns or for compliancewith specific international or national definitions.

4.f. Treatment of missing values (i) at country level and (ii) at regional level(IMPUTATION)

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At country level
Red List Indices for each taxonomic group are interpolated linearly for years between data points
and extrapolated linearly (with a slope equal to that between the two closest assessed points,
except for corals) back to the earliest time point and forwards to the present for years for which
estimates are not available. The start year of the aggregated index is set as ten years before thefirst assessment year for the taxonomic group with the latest starting point. Corals are notextrapolated linearly because declines are known to have been much steeper subsequent to 1996
(owing to extreme bleaching events) than before. Therefore, the rate of decline prior to 1996 is set
as the average of the rates for the other taxonomic groups.

•

At regional and global levels
The Red List Index is calculated globally based on assessments of extinction risk of each species
included, because many species have distributions that span many countries. Thus, while there iscertainly uncertainty around the Red List Index, there are no missing values as such, and so no
imputation is necessary.

4.g. Regional aggregations (REG_AGG)
The Red List Categories and Criteria are applied for each species on The IUCN Red List of Threatened
Species and are determined globally and provided principally by the Specialist Groups and stand-alone
Red List Authorities of the IUCN Species Survival Commission, IUCN Secretariat-led initiatives, and Red
List partner organizations. The staff of the IUCN Global Species Programme compile, validate, and curatethese data, and are responsible for publishing and communicating the results. Each individual species
assessment is supported by the application of metadata and documentation standards (IUCN 2013),
including classifications of, for example, threats and conservation actions (Salafsky et al. 2008).
Red List assessments are undertaken either through open workshops or open-access web-based
discussion fora. Assessments are reviewed by the appropriate Red List Authority (an individual ororganization appointed by the IUCN Species Survival Commission to review assessments for specificspecies or groups of species) to ensure standardisation and consistency in the interpretation of
information and application of the criteria. A Red List Technical Working Group and the IUCN Red List
Unit work to ensure consistent categorization between species, groups and assessments. Finally, aStandards and Petitions Sub-committee monitors the process and resolves challenges and disputes over
Red List assessments.
In addition, IUCN publishes guidelines on applying the IUCN Red List Categories and Criteria at regional or
national scales (IUCN 2012b). Based on these, many countries have initiated programmes to assess theextinction risk of species occurring within their borders. These countries will be able to implement the
Red List Index based on national extinction risk, once they have carried out at least two national Red Lists
using the IUCN system in a consistent way (Bubb et al. 2009). An increasing number of countries have
now completed national Red List Indices for a range of taxa (e.g., Gärdenfors 2010, Pihl & Flensted 2011).
While global Red List Indices can be disaggregated to show trends for species at smaller spatial scales, thereverse is not true. National or regional Red List Indices cannot be aggregated to produce Red List Indicesshowing global trends. This is because a taxon’s global extinction risk has to be evaluated at the global
scale and cannot be directly determined from multiple national scale assessments across its range(although the data from such assessments can be aggregated for inclusion in the global assessment).

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Methods for generating regional disaggregations of the Red List Index are described below in section 5 on
Data availability and disaggregation.

4.h. Methods and guidance available to countries for the compilation of the data at
the national level (DOC_METHOD)
Methods and guidance available to countries for the compilation of the data at the national level:
See above. In sum: the data underlying the Red List Index are compiled under the authority of the IUCNRed List Committee, through application of the IUCN Red List Categories & Criteria(https://portals.iucn.org/library/node/10315). This includes submissions of endemics from national red
list processes, where these have been conducted following the “Guidelines for application of IUCN Red
List Criteria at Regional and National Levels” (https://portals.iucn.org/library/node/10336) and following
the “Required and Recommended Supporting Information for IUCN Red List Assessments”(https://www.iucnredlist.org/resources/supporting-information-guidelines). Assessments may besubmitted in all three IUCN languages (English, French and Spanish) and Portuguese. All assessments arepeer reviewed through the relevant Red List Authority for the species or species group in question, as
documented in the Red List Rules of Procedure (https://www.iucnredlist.org/resources/rules-ofprocedure); see in particular Annex 3, the “Details of the Steps Involved in the IUCN Red List Process”(https://nc.iucnredlist.org/redlist/content/attachment_files/Details_of_the_Steps_Involved_in_the_IUCN_Red_List_Process.pdf).
The key document providing international recommendations and guidelines to countries and all involved
in application of the IUCN Red List Categories & Criteria (https://portals.iucn.org/library/node/10315) is
the “Guidelines for Using the IUCN Red List Categories and Criteria”(https://www.iucnredlist.org/resources/redlistguidelines; available in English, French, Spanish, andPortuguese) accompanied by the “Required and Recommended Supporting Information for IUCN Red List
Assessments”. For countries (and regions), this is supplemented by the “Guidelines for application of
IUCN Red List Criteria at Regional and National Levels” (https://portals.iucn.org/library/node/10336). To
support the calculation of Red List Indices for any given country (or region), “Code (and documentation)
for calculating and plotting national RLIs weighted by the proportion of each species’ distribution within acountry or region” is posted online (Dias et al. 2020; https://github.com/BirdLifeInternational/rli-codes).
Methods for generating national disaggregations of the Red List Index are described below in section 5 on
Data availability and disaggregation.

4.i. Quality management (QUALITY_MGMNT)
See above and below, and full documentation in the Red List Rules of Procedure(https://www.iucnredlist.org/resources/rules-of-procedure) in particular Annex 3, the “Details of theSteps Involved in the IUCN Red List Process”(https://cmsdocs.s3.amazonaws.com/keydocuments/Details_of_the_Steps_Involved_in_the_IUCN_Red_
List_Process.pdf).

4.j Quality assurance (QUALITY_ASSURE)

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See above, and full documentation in the Red List Rules of Procedure(https://www.iucnredlist.org/resources/rules-of-procedure) in particular Annex 3, the “Details of theSteps Involved in the IUCN Red List Process”(https://cmsdocs.s3.amazonaws.com/keydocuments/Details_of_the_Steps_Involved_in_the_IUCN_Red_
List_Process.pdf). In sum: all Red List assessments are peer reviewed through the relevant Red List
Authority for the species or species group in question; and all Red List assessments undergo consistency
checks (to ensure consistency with assessments submitted for other taxonomic groups, regions,processes, etc.) by the Red List Unit before publication on the Red List website(http://www.iucnredlist.org/). Finally, the Chair of the IUCN Species Survival Commission (elected eachfour years by the government and non-governmental Members of IUCN) appoints a Chair for a Standards
and Petitions Sub-Committee (https://www.iucn.org/our-union/commissions/group/iucn-ssc-standardsand-petitions-committee), which is responsible for ensuring the quality and standards of the IUCN Red
List and for ruling on petitions against the listings of species on the IUCN Red List.

4.k Quality assessment (QUALITY_ASSMNT)The IUCN Red List is governed by a Red List Committee (https://www.iucn.org/ourunion/commissions/group/iucn-ssc-red-list-committee), comprising representatives from the Red List
Partnership, the IUCN Species Survival Commission, and the IUCN Secretariat. This committee establishes
and maintains the Red List Strategic Plan, including ongoing evaluation of fitness for use i.e. the degree towhich the IUCN Red List meets user’s requirements. This encompasses, inter alia, considerations of
relevance, accuracy, timeliness, consistency, comprehensiveness, and accessibility.

5. Data availability and disaggregation (COVERAGE)
Data availability:
The Red List Index has been classified by the IAEG-SDGs as Tier 1. Current data are available for all
countries in the world, and these are updated annually. Index values for each country are available in the
UN SDG Indicators Database https://unstats.un.org/sdgs/indicators/database/. Red List Index graphs andunderlying index data are available for each country, SDG regions, IPBES region, CMS region and various
thematic disaggregations at https://www.iucnredlist.org/search. Red List Index graphs are also available
for each country in the BIP Indicators Dashboard(https://bipdashboard.natureserve.org/bip/SelectCountry.html), the Integrated Biodiversity Assessment
Tool Country Profiles (https://ibat-alliance.org/country_profiles), and (for birds) on the BirdLife
International Data Zone (http://datazone.birdlife.org/species/dashboard).
Disaggregation:
The Red List Index can be downscaled to show national and regional Red List Indices, weighted by thefraction of each species’ distribution occurring within the country or region, building on the method
published by Rodrigues et al. (2014) PLoS ONE 9(11): e113934. These show an index of how well species
are conserved in a country or region to its potential contribution to global species conservation (for thetaxonomic groups of species included). The index is calculated as:Last updated: 2023-12-15𝑟𝛴𝑠 (𝑊(𝑡,𝑠) ∗ ( 𝑠𝑢 ))𝑅𝑠
𝑅𝐿𝐼(𝑡,𝑢) = 1 −𝑟
𝑊𝐸𝑋 ∗ 𝛴𝑠 ( 𝑅𝑠𝑢 )𝑠where t is the year of comprehensive reassessment, u is the spatial unit (i.e. country), W_((t,s)) is theweight of the global Red List category for species s at time t (Least Concern =0, Near Threatened =1,
Vulnerable =2, Endangered =3, Critically Endangered =4, Critically Endangered (Possibly Extinct) =5,
Critically Endangered (Possibly Extinct in the Wild) =5, Extinct in the Wild =5 and Extinct =5), WEX = 5 is
the weight for Extinct species, r_su is the fraction of the total range of species s in unit u, and R_s is thetotal range size of species s.
The index varies from 1 if the country has contributed the minimum it can to the global RLI (i.e., if thenumerator is 0 because all species in the country are Least Concern) to 0 if the country has contributed
the maximum it can to the global RLI (i.e., if the numerator equals the denominator because all species in
the country are Extinct or Possibly Extinct).
The taxonomic groups included are those in which all species have been assessed for the IUCN Red List
more than once. Red List categories for years in which comprehensive assessments (i.e. those in which all
species in the taxonomic group have been assessed) were carried out are determined following theapproach of Butchart et al. 2007; PLoS ONE 2(1): e140, i.e. they match the current categories except for
those taxa that have undergone genuine improvement or deterioration in extinction risk of sufficientmagnitude to qualify for a higher or lower Red List category.
The indicator can also be disaggregated by ecosystems, habitats, and other political and geographic
divisions (e.g., Han et al. 2014), by taxonomic subsets (e.g., Hoffmann et al. 2011), by suites of species
relevant to particular international treaties or legislation (e.g., Croxall et al. 2012), by suites of species
exposed to particular threatening processes (e.g., Butchart 2008), and by suites of species that deliver
particular ecosystem services, or have particular biological or life-history traits (e.g., Regan et al. 2015). In
each case, information can be obtained from The IUCN Red List of Threatened Species to determine
which species are relevant to particular subsets (e.g., which occur in particular ecosystems, habitats, andgeographic areas of interest). These disaggregations are available on the IUCN Red List website athttps://www.iucnredlist.org/search.
Disaggregations of the Red List Index are also of particular relevance as indicators towards the following
SDG targets (Brooks et al. 2015): SDG 2.4 Red List Index (species used for food and medicine); SDG 2.5
Red List Index (wild relatives and local breeds); SDG 12.2 Red List Index (impacts of utilisation) (Butchart2008); SDG 12.4 Red List Index (impacts of pollution); SDG 13.1 Red List Index (impacts of climatechange); SDG 14.1 Red List Index (impacts of pollution on marine species); SDG 14.2 Red List Index(marine species); SDG 14.3 Red List Index (reef-building coral species) (Carpenter et al. 2008); SDG 14.4
Red List Index (impacts of utilisation on marine species); SDG 15.1 Red List Index (terrestrial & freshwater
species); SDG 15.2 Red List Index (forest-specialist species); SDG 15.4 Red List Index (mountain species);
SDG 15.7 Red List Index (impacts of utilisation) (Butchart 2008); and SDG 15.8 Red List Index (impacts ofinvasive alien species) (Butchart 2008, McGeoch et al. 2010).

6. Comparability / deviation from international standards (COMPARABILITY)Last updated: 2023-12-15

Sources of discrepancies:
Some countries have assessed the national extinction risk of species occurring in the country, and haverepeated such assessments, allowing a national Red List Index to be produced. This may differ from theindicator described here because (a) it considers national rather than global extinction risk, and (b)because it takes no account of the national responsibility for the conservation of each species, treating as
equal both those species that occur nowhere outside the country (i.e. national endemics) and those withlarge ranges that occur in many other countries. Any such differences will be smaller for countries within
which a high proportion of species are endemic (i.e., only found in that country), as in many island
nations and mountainous countries, especially in the tropics. The differences will be larger for countries
within which a high proportion of species have widespread distributions across many nations.

7. References and Documentation (OTHER_DOC)
URL:
https://www.iucn.org/assessment/red-list-index
References:
These metadata are based on https://www.bipindicators.net/indicators/red-list-index and thereferences listed below.
BAILLIE, J. E. M. et al. (2004). 2004 IUCN Red List of Threatened Species: a Global Species Assessment.
IUCN, Gland, Switzerland and Cambridge, United Kingdom. Available fromhttps://portals.iucn.org/library/node/9830.
BROOKS, T. M. et al. (2015). Harnessing biodiversity and conservation knowledge products to track the
Aichi Targets and Sustainable Development Goals. Biodiversity 16: 157–174. Available fromhttp://www.tandfonline.com/doi/pdf/10.1080/14888386.2015.1075903.
BUBB, P.J. et al. (2009). IUCN Red List Index - Guidance for National and Regional Use. IUCN, Gland,
Switzerland. Available from https://portals.iucn.org/library/node/9321.
BUTCHART, S. H. M. et al. (2010). Global biodiversity: indicators of recent declines. Science 328: 1164–
1168. Available from https://www.science.org/doi/10.1126/science.1187512.
BUTCHART, S. H. M. (2008). Red List Indices to measure the sustainability of species use and impacts ofinvasive alien species. Bird Conservation International 18 (suppl.): 245–262. Available fromhttp://journals.cambridge.org/action/displayJournal?jid=BCI.
BUTCHART, S. H. M. et al. (2007). Improvements to the Red List Index. PLoS ONE 2(1): e140. Available
from http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0000140.
BUTCHART, S. H. M. et al. (2006). Biodiversity indicators based on trends in conservation status: strengthsof the IUCN Red List Index. Conservation Biology 20: 579–581. Available fromhttp://onlinelibrary.wiley.com/doi/10.1111/j.1523-1739.2006.00410.x/abstract.

Last updated: 2023-12-15

BUTCHART, S. H. M. et al. (2005). Using Red List Indices to measure progress towards the 2010 target andbeyond. Philosophical Transactions of the Royal Society of London B 360: 255–268. Available fromhttp://rstb.royalsocietypublishing.org/content/360/1454/255.full.
BUTCHART, S. H. M. et al. (2004). Measuring global trends in the status of biodiversity: Red List Indices forbirds. PLoS Biology 2(12): e383. Available fromhttp://www.plosbiology.org/article/info:doi/10.1371/journal.pbio.0020383.
CARPENTER, K. E. et al. (2008). One-third of reef-building corals face elevated extinction risk from climatechange and local impacts. Science 321: 560–563. Available fromhttps://www.science.org/doi/10.1126/science.1159196 .
CBD (2014). Global Biodiversity Outlook 4. Convention on Biological Diversity, Montréal, Canada.
Available from https://www.cbd.int/gbo4/.
CBD (2020a). Global Biodiversity Outlook 5. Convention on Biological Diversity, Montréal, Canada.
Available from https://www.cbd.int/gbo5/.
CBD (2020b). Post-2020 Global Biodiversity Framework: Scientific and technical information to support
the review of the updated Goals and Targets, and related indicators and baselines. Document
CBD/SBSTTA/24/3. Available at:https://www.cbd.int/doc/c/705d/6b4b/a1a463c1b19392bde6fa08f3/sbstta-24-03-en.pdf.
DIAS, M.P, SIMKINS, A.T., & PEARMAIN, E.J. (2020). Code (and documentation) for calculating andplotting national RLIs weighted by the proportion of each species’ distribution within a country or region.
https://github.com/BirdLifeInternational/rli-codes.
CROXALL, J. P. et al. (2012). Seabird conservation status, threats and priority actions: a global assessment.
Bird Conservation International 22: 1–34.
GÄRDENFORS, U. (ed.) (2010). Rödlistade arter i Sverige 2010 – The 2010 Red List of Swedish Species.
ArtDatabanken, SLU, Uppsala.
HAN, X. et al. (2014). A Biodiversity indicators dashboard: addressing challenges to monitoring progress
towards the Aichi Biodiversity Targets using disaggregated global data. PLoS ONE 9(11): e112046.
Available from http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0112046.
HOFFMANN, M. et al. (2010). The impact of conservation on the status of the world’s vertebrates.
Science 330: 1503–1509. Available from https://www.science.org/doi/10.1126/science.1194442.
HOFFMANN, M. et al. (2011). The changing fates of the world’s mammals. Philosophical Transactions of
the Royal Society of London B 366: 2598–2610. Available fromhttp://rstb.royalsocietypublishing.org/content/366/1578/2598.abstract.
IUCN SPSC (2019) Guidelines for Using the IUCN Red List Categories and Criteria. Version 14. International
Union for Conservation of Nature – Standards and Petitions Subcommittee, Gland, Switzerland. Available
from https://www.iucnredlist.org/resources/redlistguidelines.

Last updated: 2023-12-15

IUCN (2012a). IUCN Red List Categories and Criteria: Version 3.1. Second edition. International Union forConservation of Nature, Gland, Switzerland. Available from https://portals.iucn.org/library/node/10315.
IUCN (2012b). Guidelines for Application of IUCN Red List Criteria at Regional and National
Levels: Version 4.0. International Union for Conservation of Nature, Gland, Switzerland. Available fromhttps://portals.iucn.org/library/node/10336.
IUCN (2013). Documentation Standards and Consistency Checks for IUCN Red List assessments andspecies accounts. International Union for Conservation of Nature, Gland, Switzerland. Available fromhttps://www.iucnredlist.org/resources/supporting-information-guidelines.
IUCN (2015). IUCN Red List of Threatened Species. Version 2015.1. International Union for Conservationof Nature, Gland, Switzerland. Available from http://www.iucnredlist.org.
MACE, G. M. et al. (2008) Quantification of extinction risk: IUCN’s system for classifying threatened
species. Conservation Biology 22: 1424–1442. Available fromhttp://onlinelibrary.wiley.com/doi/10.1111/j.1523-1739.2008.01044.x/full.
MCGEOCH, M. A. et al. (2010) Global indicators of biological invasion: species numbers, biodiversity
impact and policy responses. Diversity and Distributions 16: 95–108. Available fromhttp://onlinelibrary.wiley.com/doi/10.1111/j.1472-4642.2009.00633.x/abstract.
PIHL, S. & FLENSTED, K. N. (2011). A Red List Index for breeding birds in Denmark in the period 19912009. Dansk Ornitologisk Forenings Tidsskrift 105: 211-218.
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doi: 10.1111/conl.12162. Available fromhttp://onlinelibrary.wiley.com/doi/10.1111/conl.12162/abstract.
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