Variables and Data

The NATO Burden Sharing Project relies on six key variables shown below. In order to avoid comparing apples to oranges, we calculated a z-value for each of the six variables. Z-values are used to generate a unitless measure of each Ally’s performance under each variable. In statistical analysis, a z-value is the number of standard deviations of a given value away from the mean or some other target value (e.g., spending 20 percent of the defense budget on acquisition). In other words, z-values measure the dispersion, or spread of the data. The z-values for each Ally were calculated by taking a given value for one country from the data, subtracting that value from the average or target, and dividing by the standard deviation. Allies that are wildly above or below the average or target are penalized.

Click on each one to learn more about each variable and the sources of the data used to generate the dashboard. To obtain a copy of the data, please submit an inquiry on the Contact Page.

Defense Expenditure as a Share of GDP

This variable comprises 25 percent of the NATO Burden Sharing Project score.

Military expenditure as a percentage of GDP is a heavily weighted variable in our calculations of defense inputs. This is commonly referred to as the ‘2 percent’ benchmark, part of NATO’s Defence Investment Pledge made during the 2014 Wales Summit. Although insufficient in isolation, the 2 percent spending metric remains an essential element in determining burden sharing because it indicates an Ally’s defense spending relative to its ability. Data is based on the Defence Expenditure of NATO Countries (2014-2021), available at https://www.nato.int/cps/en/natohq/news_193983.htm.

Defense Expenditure by Category

This variable comprises 15 percent of the NATO Burden Sharing Project score.

As part of the Defence Investment Pledge made at the Wales Summit in 2014, allies committed to spending at least 20 percent of their defense budgets on major equipment and related research and development. Although NATO measures defense expenditure across four main categories -- equipment, personnel, infrastructure, and 'other' (which consists mostly of current operations) -- it only maintains a spending goal for equipment (and related R&D). The folks who built the NATO Burden Sharing Project thinks there should be targets for the other categories as well, based in part on averages across the alliance, as follows: 3 percent on infrastructure, 45 percent on personnel, and 32 percent on 'other'. Scores for this variable are based on the degree to which each ally is close to the target -- the further away from the target, either positive or negative, the worse the score. Data is based on the Defense Expenditure of NATO Countries (2014-2021), available at https://www.nato.int/cps/en/natohq/news_193983.htm.

Troops per Capita

This variable comprises 10 percent of the NATO Burden Sharing Project score.

Over the last decade, it has become clear that large scale warfare has returned to Europe. Capacity therefore is critical for the alliance. This variable ranks each NATO ally based on the number of active-duty troops per capita. The definition of ‘active’ troops includes all personnel on full-time duty (including conscripts and long-term reservist assignments). When a gendarmerie (a military force with law enforcement duties among the civilian population) or equivalent is under control of the defense ministry, they may be included in the active total. Data comes from the 2022 IISS Military Balance.

Force Usability

This variable comprises 20 percent of the NATO Burden Sharing Project score.

Although NATO has its own system of measuring levels of readiness for allied military units, as well as various evaluations of their performance during training events and exercises, this information is not publicly available. For this reason, we must evaluate each ally's force usability some other way.

The United Nations publishes some of its capability requirements for military task forces. One such standard is the Rapid Deployment Level (RDL) of the Peacekeeping Capability Readiness System (PCRS). The PCRS is the system utilized by troop contributing countries (TCCs) to declare what resources they pledge to the UN, as well as what readiness level those units may be considered. The RDL itself is the highest (most ready) of the system’s four levels of readiness: Level 1, Level 2, Level 3, and RDL. To be considered RDL, a brigade of 4,000 troops must have the following 15 units:
* Armed Utility Helicopter Unit
* Attack Helicopter Unit
* Medium Utility Helicopter Unit
* Transport Aircraft Company
* Transport Unit
* Infantry Battalion
* Logistics Battalion
* Engineer Company
* Signals Company
* HQ Support Company
* Force Protection Company
* Level 2 Hospital
* Military Police Company
* Quick Reaction Force Company
* Special Forces Company

Since NATO also uses standing high readiness task forces for which allies identify units, it stands to reason that the requirements between the two would be similar. As such, we can evaluate the force usability of each TCC by the number of these units that it could contribute on its own. The more units a nation can commit on its own to such a task force, the more usable that nation’s forces are.

We evaluated the capabilities of each NATO member by comparing this list of unit requirements to the IISS Military Balance (https://www.iiss.org/publications/the-military-balance/the-military-balance-2021) evaluation of the capacity of European and North American militaries. For each required unit that an ally possesses, that ally is given a point, as it is considered capable of contributing that unit to NATO. The total number of points out of 15 is that nation’s force usability score, with those closest to the required 15 being the most useable. Of course, by relying on the UN’s RDL standards to approximate NATO forces’ usability, we narrowed our focus mostly to ground forces, with some close air support and airlift included. Also, the definition of “rapid deployment” varies slightly between NATO and the UN. RDL standards require initial deployment within 60 days. In contrast, NATO’s Rapid Deployable Corps’ published requirements state that the first elements of a corps should be deployable within ten days, while the whole force should be deployable within 60 days.

Military Mobility

This variable comprises 10 percent of the NATO Burden Sharing Project score.

Military mobility is used in the NATO Burden Sharing Project as a proxy variable for deployability. Military mobility is an essential element of effective defense and deterrence. NATO’s forces must have the capability to rapidly organize and deploy faster than the adversary.

There are eight constituent elements of rapid military mobility comprising this variable, grouped into two categories: 1) cross border military mobility, and 2) air movement. The former includes: Aerial Ports of Debarkation (APODs), Seaports of Debarkation (SPODs), Road Systems, Rail Heads, and Diplomatic Clearance. The second consists of Overflight Clearance, Landing Approval, and Clearance Windows for Time on Ground. Data is based on research discussions with USAREUR-AF and USAFE.

There are two important caveats. First, the data here is based on peacetime movement of military assets. It is possible clearance times would be shorter if Article 5 was invoked or an ally declares a national emergency.

Second, we were not able to gather comparable data for the North American allies. However, the United States and Canada do not face the same complex challenges to cross-border mobility that European Allies do. Regardless, this means Canada may be unfairly undervalued (or perhaps overvalued) and that may have affected their rank in the final burden sharing model score. The same is true for the United States.

Though the data gathered for this variable is highly useful, it does not measure other aspects of deployability including the readiness and training of the troops, the state of repair/disrepair of equipment, and the overall organizational and operational capability of a given ally to handle the rapid deployment of troops and equipment. Though these are important measures of deployability, we were unable to identify publicly available data to study these key areas.

Current Operations Contributions

This variable comprises 20 percent of the NATO Burden Sharing Project score.

Contributing troops to NATO missions represents a key measure of an ally’s commitment to the security of the alliance and its military operations and missions. This variable includes data on each ally's contribution to the Enhanced Forward Presence (EFP) mission as of February 2022 as a percent of all troops contributed to EFP. The EFP mission was used because it is land force intensive, and nearly all allies have land forces. Data is based on the NATO EFP 'placemat' for February 2022 (https://www.nato.int/nato_static_fl2014/assets/pdf/2022/2/pdf/2202-factsheet_efp_en.pdf).