A recent report from the Office of National Drug Control Policy estimates that only $9 billion is spent annually on marijuana in the United States, whether foreign or domestic.(153) The estimate is based solely on National Household Survey data estimating the prevalence, frequency, and amount of marijuana use in the U.S. The author's admit the $9 billion figure is conservative.

"These estimates are probably low. Users are likely to underreport socially disapproved behaviors even when those behaviors are legal. They would seem to have even more incentive to underreport illegal behaviors. Some readers might find it reasonable to inflate these estimates for marijuana consumption by about one-third."(154)

Another problem for consumption estimates based on the National Household Survey is presented by the limitations of the data. While the survey does solicit data about the gross amount of marijuana used by the respondent in the last month, it triangulates that information with data on the average number of joints used in the same time period. This sort of analysis assumes that every marijuana user smokes marijuana by way of a cigarette, ignoring the popularity of waterpipes among marijuana users, especially college-aged consumers. Smokers of marijuana cigarettes are likely to consume more marijuana than waterpipe or pipesmokers to achieve the same subjective high because, as discussed in section 2, the delivery efficiency of each mode of smoking varies. This may seem like a small problem, and perhaps it is, however the NHS data set has a lot of missing data in it, and this data is replaced with data that is "imputed" from the available data. Depending on the amount of imputed data used in the estimate, assumptions about usage patterns could become very significant to the accuracy of the estimate.

Gettman has analyzed DEA Eradication program reports for the National Organization for the Reform of Marijuana Laws, and based on these reports has formulated estimates of the size and value of the domestic marijuana crop.(155) These reports have been highly critical of the data used by DEA in estimating marijuana prices in the United States, and in DEA's self-serving estimates of the domestic marijuana crop size. A 1994 paper from the Office of National Drug Control Policy voices many of the same criticisms about the price data presented by DEA, and like the 1993 NORML report incorporates price information reported in High Times magazine.(156) This report is also critical of DEA's crop estimates:

"Clearly, DEA estimates of domestic marijuana production are not consistent with the consumption-based estimate. Not only is the DEA estimate of 1992 production approximately triple the consumption-based figure, but DEA data also suggests a roughly fifty percent decline in domestic marijuana cultivation from 1990 to 1992. By comparison, user surveys indicate only a twenty percent drop in consumption over the same period."(157)

"If we take the 1992 total eradication figure, and use a conservative yield estimate of one half pound for commercial grade and one quarter pound per plant for sinsemilla (DEA estimates a yield of a full pound per plant regardless of type), the eradication and suppression program appears to have prevented about 1,475 metric tons from being harvested. When combined with the estimate of total domestic marijuana production, this implies that roughly sixty percent of domestically grown marijuana is eradicated. This seems unlikely. A plausible explanation for the apparent inconsistency is that a substantial fraction of the marijuana eradicated by authorities and reported as sinsemilla or commercial grade is in fact "ditchweed", a very low potency generally less than 1 percent THC) variety of marijuana that grows wild in much of the U.S."(158)

The DEA has easily withstood such criticism from NORML, and has since the mid 1980's. However such negative criticism from the ONDCP could not be ignored; the DEA gave up trying to estimate the size of the domestic marijuana crop in the United States. According to a note in the 1995 ONDCP report:

"The DEA no longer estimates the amount of marijuana under cultivation in the United States. The DEA also notes that indoor marijuana cultivation continues and that there is no way to estimate the extent of this practice."(159)

Consequently, without an estimate of U.S. domestic marijuana supply it is impossible to develop a supply-based estimate of the retail marijuana market in the U.S. with which to compare the $9 billion consumption based estimate.

"It is difficult to develop an estimate of the size of the U.S. retail market for marijuana from estimates of available supply. First, the amount of marijuana that Americans cultivate for personal use is impossible to estimate. Second, even though a large amount of the domestic marijuana market is grown in the United States, countries in South and Central America, the Caribbean, Asia, North Africa, and the Middle East also supply cannabis to the domestic market. Unfortunately, the data needed to develop better estimates are not available, and without the independent ability to assess the reliability of the marijuana cultivation estimates, we cannot develop a plausible supply-based estimate of the retail value of the marijuana market in the United States."(160)

In other words, the scope of marijuana cultivation in the United States is so immense that the government has just admitted that it exceeds characterization. If it is impossible to even estimate personal cultivation, then it is patently absurd to believe that marijuana's schedule I status can ever be enforced by law enforcement officials. Enforcement of the Controlled Substances Act is premised on control and regulation of drug manufacture and supply.