An alternative hypothesis is that there are no discrete trajectory groups to be uncovered. From this perspective, alcohol use is a behavior that fluctuates uniquely for each (non-abstaining) person, and these unique, individual pathways cover the entire developmental terrain. A familiar example is the pediatric growth chart, which shows percentile trajectories for height or weight across the first few years of a child’s development. Such charts show the average trajectory of growth—faster at first and then slowing with age—as well as a “rainbow” of percentile trajectories around the average that represent lower and higher rates of growth. Growth charts do not portray development in categorical terms, where children are grouped into one of a few distinct trajectories; rather, growth charts portray a continuous developmental landscape.
