Why the sources are deliberately uneven
The six source families are uneven on purpose. They range from institutional reports with a two-year lag to social platforms with a two-day one. Institutional publications tell you what has already been agreed is important, which is useful and always late. Social platforms tell you what is being felt before anyone has written it down, which is early and mostly noise.
Neither substitutes for the other. A scan drawing only on the respectable half of that list will reliably produce a picture of the recent past with the dates changed. A scan drawing only on the fast half will mistake a fortnight for a trend.
The narrowing, and what it costs
The narrowing takes four moves: collect, tag and categorise, interpret, prioritise. The first is easy and the second is tedious. The third is where the thinking happens, and the fourth is where the exercise either earns its credibility or quietly loses it.
We prioritised against the system’s stated aims. That is defensible, and it has a cost. Judging a signal by its fit with what the system has already committed to filters out the signals most worth attending to: the ones that would require a commitment to be revisited. I do not know a clean way around this. The partial remedy is to keep a visible list of what was discarded and why, so the filter can be argued with later rather than disappearing into the process.
Seven lenses, and what they are actually for
Signals were read through seven lenses: the familiar social, technological, economic, environmental and political set, plus demographic and pedagogical. We added those two because a scan for schools that cannot see enrolment decline or teaching practice is not a scan for schools.
The lenses do a procedural job, and they partition nothing cleanly. They force a signal to be looked at from a direction the person holding it would not have chosen. Almost every useful reading in the exercise came from a signal being made to answer a lens it did not obviously belong to.