Cir­cuitous thought-the myth of reli­able and valid mar­i­juana iden­ti­fi­ca­tion in the courtroom

By:  Fred­eric White­hurst, J.D., Ph.D. [1]

As sci­en­tists we all agree that the hall­marks of sci­ence are valid­ity and reli­a­bil­ity. What do we mean by that? Well, the gov­ern­ment sci­en­tist has to agree that his method of answer­ing a ques­tion put to him has to be valid and reli­able. So no mat­ter how he iden­ti­fies mar­i­juana that method must be valid and reli­able. Sci­en­tists deter­mine valid­ity and reli­a­bil­ity with data. What does valid­ity mean? It means that the method we use to answer a ques­tion must appro­pri­ate for the use to which we put it. Bet­ter said, just because we have a ham­mer does not mean every­thing is a nail.

The ques­tion we are ask­ing about mar­i­juana is “Is this mate­r­ial mar­i­juana?” That means is it mar­i­juana to the exclu­sion of all other plants? So we have to have a pro­to­col that will show us that the mate­r­ial we have is mar­i­juana to the exclu­sion of all other plants. In order to show that our pro­to­col is valid we must either have tested all other plants or have a the­o­ret­i­cal argu­ment as to why no other plant can be mis­taken for mar­i­juana using our pro­to­col. The only attempt at val­i­da­tion that has been con­ducted in the past is the work of George Naka­mura and John Thorn­ton back in the early 1970’s. That did not show the pro­to­col iden­ti­fied mar­i­juana to the exclu­sion of all other plants but only tested the pro­to­col on 31874 plants. So no one has val­i­dated the pro­to­col. The gov­ern­ment sci­en­tist can not show that. In a Frye state we accept the opin­ion if the method used to arrive at it is accepted by the com­mu­nity of peers. The com­mu­nity of peers do not accept that the mar­i­juana analy­sis pro­to­col is valid because no one has val­i­dated the pro­to­col. They just use the method. No one has val­i­dated it. As for reli­a­bil­ity, that means if the tests is per­formed by one per­son many times or by many peo­ple will one get the same answer. How­ever, there are no reli­a­bil­ity stud­ies known. Gov­ern­ment sci­en­tists sim­ply say that they always get the right answer and never have got­ten the wrong answer but they are not being tested for reli­a­bil­ity with known stan­dards. They are sim­ply say­ing that the unknowns must be mar­i­juana because the police say they are mar­i­juana so they must be marijuana.

Cir­cuitous thought. Wrong think­ing. Com­pound that with the paucity of sci­en­tific data that exists to test the reli­a­bil­ity hypoth­e­sis and you have noth­ing to refer to to indi­cate that the pro­to­col is actu­ally reli­able. So the peer group would agree that in order for the pro­to­col to be used it must be shown to be valid and reli­able and it has not been shown to be so it can’t be used…but they use it anyhow.

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[1] Exec­u­tive Direc­tor, Foren­sic Jus­tice Project, Wash­ing­ton, D.C., B.S. Chem­istry, 1974, East Car­olina Uni­ver­sity, Ph.D. in Chem­istry, 1980, Duke Uni­ver­sity, J.D., 1996, George­town Uni­ver­sity School of Law. (202)342‑6980.