The studies were scored blind to treatment condition.

Together, these studies included 1039 participants in treatment conditions and 951 in control conditions.

Abstinence rates at four months were 37% for both active groups, compared to 9% for the delayed treatment condition.

Clinical case reports in the treatment orthopaedic conditions have been reported.

Pilot tests to develop treatment conditions are generally not necessary for petroleum-contaminated soils.

In some cases, the researcher may have no control over assignment to treatment condition.

With quasi-experimental studies, it may not be possible to convincingly demonstrate a causal link between the treatment condition and observed outcomes.

In an experiment with random assignment, study units have the same chance of being assigned to a given treatment condition.

In a quasi-experimental design, assignment to a given treatment condition is based on something other than random assignment.

It is important to note that the start of treatment conditions is staggered (started at different times)across individuals.