Technology and patent cartels share knowledge about technology or science within themselves while they limit the information from outside individuals. Condition cartels unify contractual terms – the modes of payment and delivery, or warranty limits. Standardization cartels implement common standards for sold or purchased products. If the members of a cartel produce different sorts or grades of a good, conversion factors are applied to calculate the value of the respective output. Compulsory cartels, also called "forced cartels", are established or maintained by external pressure. Voluntary cartels are formed by the free will of their participants. Effects A survey of hundreds of published economic studies and legal decisions of antitrust authorities found that the median price increase achieved by cartels in the last 200 years is about 23 percent. Private international cartels (those with participants from two or more nations) had an average price increase of 28 percent, whereas domestic cartels averaged 18 percent. Less than 10 percent of all cartels in the sample failed to raise market prices. In general, cartel agreements are economically unstable in that there is an incentive for members to cheat by selling at below the cartel's agreed price or selling more than the cartel's production quotas. Many cartels that attempt to set product prices are unsuccessful in the long term because of cheating punishment mechanisms such as price wars or financial punishment. An empirical study of 20th-century cartels determined that the mean duration of discovered cartels is from 5 to 8 years and overcharged by approximately 32%. This distribution was found to be bimodal, with many cartels breaking up quickly (less than a year), many others lasting between five and ten years, and still some that lasted decades. Within the industries that have operating cartels, the median number of cartel members is 8. Once a cartel is broken, the incentives to form a new cartel return, and the cartel may be re-formed. Publicly known cartels that do not follow this business cycle include, by some accounts, OPEC. Cartels often practice price fixing internationally. When the agreement to control prices is sanctioned by a multilateral treaty or protected by national sovereignty, no antitrust actions may be initiated. OPEC countries partially control the price of oil, and the International Air Transport Association (IATA) fixes prices for international airline tickets while the organization is excepted from antitrust law. Organization Drawing upon research on organizational misconduct, scholars in economics,