These figures show how well the test strips used by drug checking technicians in Massachusetts matched laboratory results by comparing strip results (positive or negative) with lab test findings. The results are grouped into cases where the test strip and lab agreed (true positives and true negatives) and cases where they did not agree (false positives and false negatives). Agreement means the test strip result was the same as the lab result. Disagreement means the results were different. Each bar shows how many samples had a positive or negative strip result, and the stacked sections show whether the lab test agreed or disagreed with that result.​