Observations. This blog has hundreds of observations – “This law department does or did something.” The department observed could be one-of-a-kind, or it could be among the lemmings.
Trends. Multiple observations of a similar activity leads to talk of a trend. The word trend leaves the impression of a prediction: more and more law departments track time, so the incidence of adoption will climb in the future. Just because some activity “is growing in frequency” is, strictly speaking, merely to note what has been happening; but if noting that increase implies that the activity will continue, then the observer has concluded that there is a trend.
A trend-based prediction drops us immediately into the fallacy of induction, which is the tendency to generalize from past to future without an adequate theoretical basis. What we especially need to avoid are naïve extrapolations from existing trends. Most people overlook that a bad trend often contains within itself the seeds of reversal. For example, more law departments may have experimented with cubicles for lawyers (aha, a trend!) but the consequences to morale and productivity may halt the spread of that practice.
Predictions. A prediction need have neither observations nor trends, but most do. I believe I can predict multidisciplinary law practices now, where non-lawyers share in legal profits with lawyers, based not on any examples in the US let alone stepping-stone instances that suggest a trend, but based simply on economic forces likely to bring about the change over time.