Outcome measures | How the outcome measures were sourced and quantified |
---|---|
Comparison of effectiveness | |
Heroin use | Based on self-reported heroin use at each of the five time-points. The question was ‘During the last 3 months, did you use heroin?’ The answer was ‘Yes’ or ‘No’ (dichotomous outcome variable created in the data set with Yes = 1 and No = 0). Results of urine drug screening were used to validate self-reported heroin use. |
Drug-free days (in the preceding 30 days) | The question asked was ‘During the previous 30 days, on average, how many days did you NOT use any illicit drugs?’ The value to this question formed the basis for a continuous outcome variable with the range from 0 to 30 (drug-free days). |
Drug-use related illegal behaviors | A list of 6 questions about drug-use related illegal behaviors was asked; each focused on a type of illegal behavior: a) Using force to get money from other people; b) Fraud; c) Theft; d) Robbery; e) Illicit drug dealing; and f) Assault, physical flight to get money to buy illicit drugs. A dichotomous variable (Yes/No) was created for this outcome measure with all illegal behaviors combined. |
Drug-used related BBV risk behaviors | The BBV-TRAQ-SV [46] was used to create data for this outcome measure. Answers to all questions were counted and a single summary score was calculated. |
Overdose incident | The question was ‘Did you experience any overdose incident during the previous 3 months?’ A dichotomous outcome variable was created with Yes = 1 and No = 0. |
Monthly drug spending | Answers to 4 questions were used to calculate the value for this outcome variable: ‘The number of days using illicit drugs monthly?’ ‘List of the three drugs that you used the most frequently during the last 3 months?’ ‘For each of the three drugs, how much money did you spend for one time of use?’ ‘What was the frequency of use for each of the 3 drugs?’ The following formula was used to calculate the amount of monthly drug spending for each drug: MonthlySpending = (NumberOfDaysUse*DrugDailyFrequency*AmountSpent) + (DrugWeeklyFrequency*4 (weeks)*AmountSpent) + (DrugMonthlyFrequency*AmountSpent) The amount of monthly spending for all three drugs were added together and the value formed a continuous outcome variable. |