This variable contains a taxonomy of the basic types of policies and institutions that a governance system uses in order to affect actor behavior and achieve commons outcomes. It fairly directly relates to the literature on environmental policy instrument choice (e.g. see , although it uses some of its own terminology, avoiding loaded terms such as "command and control." These policies are also related to each other in a small hierarchy, which is presented in the following indented list:

• Output-based standards

• Outcome-based ambient standards / rights
• Proportional outcome-based performance standards
• Absolute outcome-based performance standards
• Market-based instruments

• Input-based standards
• Technological standards
• Technological prohibitions
• Technological mandates
• Temporal standards
• Bans
• Market-based standards
• Price ceiling
• Price floor
• Incentive-based instruments
• Tax
• Subsidy
• Joint tax-subsidy
• Payment for ecosystem services (PES) schemes
• Market-based instruments
• Information provision
• Insurance provision
• Protected area

Standards and rights: Standards are distinguished from other instruments in that they all are constituted by rules that are highly prescriptive. They generally mandate, permit, and forbid various behaviors or outcomes.

Output-based standards are distinguished from input-based standards (terminology borrowed from fishery policy literature) in that the former mandate or forbid certain outcomes, whereas the latter mandate or forbid certain actions and behaviors.Property rights are frequently considered to be a separate category of instrument, and certainly not considered to be related to restrictions, but in effect they are closely related to standards as just defined. The reason is that standards that restrict behavior and rights that grant behavior are really two sides of the same coin. A right that states that an individual may extract X amount of a resource implies a restriction that they cannot extract more than X. And vice versa. The two languages are essentially two ways of describing the same thing. As a result, we do not include a separate property right-based instrument here. Rather, we label standards as joint standards/rights when appropriate. A subset of the following standards also involve the granting of rights.

There are several types of output-based standards:

Outcome-based ambient standards: Is a restriction on an environmental parameter (frequently the concentration or quantity of a pollutant or natural resource) specific to a particular spatial area. A particular example is the National Ambient Air Quality Standards (NAAQS) within the United States Clean Air Act regime, which established maximum concentrations of certain pollutants in certain airsheds.

An outcome-based performance standard is a right/restriction that specifies a particular quantity of a commons that can be used (emitted or extracted). Examples include individual fishing quotas, or the rights given to individual polluters in cap-and-trade systems. There are two subytpes of outcome-based performance standards, based on the rights granted to actors in the system:

Market-based instruments: Market-based instruments are ofter referred to as their own type of instrument, but are really performance standards, the rights to which are transferable (tradable). The two most popular examples of these instruments are "cap-and-trade" and "individual transferable quota" instruments in pollution and fisheries sectors, respectively. The involve an initial cap and then grant rights of one sort or another to commons users in an amount that equates to the cap.

Proportional outcome-based performance rights/standards: These grant actors the right to use a proportional amount of a commons, based on a measurement of the total amount of that commons that is available. These are used in many natural resource management contexts. An example of a proportional standard is the 1944 US-Mexico Treaty that divides the Rio Grande. This treaty grants 2/3 of the available water to Mexico, with the remainder going to the United States.

Absolute outcome-based performance rights/standards: These grant actors the right to use an absolute amount of a commons, regardless of current levels of use or availability. An example of absolute standards is the management of water in the "lower basin" of the Colorado River Compact, which grants states absolute amounts of water. An absolute ban on any commons use is a type of absolutely outcome-based standard. Input-based standards: Input-based standards are not on option here, but all of the following options are examples of input-based standards. These all grant rights and establish restrictions based on a certain way of using (extracting or emitting) a commons.

Technological standards: Grant rights and establish restrictions that require or prohibit the use of certain technologies when a commons is used. Examples include gear restrictions in fisheries, and the requirement to use Sulfur scrubbers as mandated by the U.S. Clean Air Act Amendments.

Temporal rights/standards: These grant actors the right to use a commons for a particular period of time. Examples would include a seasonal closure of a fishery, or the right of farmers to irrigate in a sequence for a particular number of hours each day. In Mexico, actors are limited to driving during certain hours of the day.

Bans: A ban is an absolute limit on the use of a commons.

Market-based standards: These standards are specific to market prices, and mandate that the price of a traded good (in this case a good associated with a commons) shall not fall below a certain limit (price floor) or exceed a certain limit (price ceiling).

Incentive-based instruments: These are not as prescriptive as standards. Instead, they attempt to change and affect behavior by affecting the costs and benefits associated with certain actions without formally mandating or prohibiting behaviors or outcomes. There are two basic types: taxes, which add costs to certain activities, and subsidies, which add benefits to certain activities. These can be combined in a single instrument, in the case of deposit-refund schemes in the U.S.

Payment for ecosystem services: These regimes involve the construction of a contract that offers payments to resource users in order to encourage them to manage their resources in a way that produces important public goods. It is similar to a subsidy if the payments are made by a governmental body, but is frequently called by this particular name.

Information provision: These regimes are designed to increase information about the state of a commons, use dynamics (extraction or emission rates) or about goods associated with the use of a commons. A U.S. example includes the "Toxic Release Inventory" program.

Insurance provision: insurance instruments insure commons users against damaging outcomes in the case of risky environments. A common environmental example is crop insurance for farmers.

Protected area: A protected area is "A protected area is a clearly defined geographical space, recognized, dedicated and managed, through legal or other effective means, to achieve the long-term conservation of nature associated with ecosystem services and cultural values"
(http://worldparkscongress.org/about/what_are_protected_areas.html