Testing for Drugs

Over a million people a year are arrested in the United States on charges of illegal drug possession. Many of them are tested in the field (say at a traffic stop) for drugs. Unfortunately, these field tests are far from infallible. In a 1974 study the National Bureau of Standards warned that the field test kits “should not be used as sole evidence for the identification of a narcotic or drug of abuse.” By 1978, the Department of Justice had determined that field tests “should not be used for evidential purposes,” and the field tests in use today remain inadmissible at trial in nearly every jurisdiction; instead, prosecutors must present a secondary lab test using more reliable methods.

Yet, many people go to jail as a result of these field tests. RTI International, a nonprofit research group based in North Carolina, found that prosecutors in nine of 10 jurisdictions it surveyed nationwide accepted guilty pleas based solely on the results of field tests, and ProPublica confirmed that prosecutors or judges accept plea deals on that same basis in many cities across the country.

Often, people caught by these field tests are so worried that they plead guilty even though they have no drugs. One study found that more than 10 percent of all county and state felony convictions are for drug charges, and at least 90 percent of those convictions come by way of plea deals. A majority of those are felony convictions, which restrict employment, housing and — in many states — the right to vote.