League strength
Comparing players from different countries requires knowing what each league is worth. Data'Scout places more than 115 competitions on a common scale, reassessed regularly. That hierarchy is the backbone of the performance index: it is what allows a successful season here to weigh more than a successful season there.
Why an explicit hierarchy is needed
Every scout carries a hierarchy of leagues in his head, built through experience. The problem is that it is implicit, varies from person to person, and is rarely reliable beyond a handful of well known countries.
Making that hierarchy explicit and identical for everyone changes the nature of internal discussions. A disagreement about a player becomes a disagreement about the player again, rather than about the assumed value of his league.
A scale that moves
The level of a competition is not fixed. Broadcasting rights, European results, incoming investors and development cycles shift leagues along the scale within a few seasons. The hierarchy is therefore reassessed, and a comparison made three years ago does not necessarily hold today.
That is especially true of mid tier divisions, where most of the recruitment happens for clubs without top table resources.
What the hierarchy does not tell you
It describes the average level of a competition, not that of each of its clubs. In many countries, the gap between the top and bottom of a league far exceeds the gap between two neighbouring leagues on the scale.
It says nothing about style either. Two leagues of equivalent level can demand very different qualities, which is why a player can succeed in one and fail in the other without any hierarchy having predicted it.
Frequently asked questions
How do you compare a second division player with a Championship player?
By going through a league hierarchy that places both competitions on the same scale. That is what the performance index does: it brings performances produced in different contexts onto a comparable basis.
Is league strength fixed?
No, it is reassessed regularly. A league that gains economic pull or improves in European competition climbs the scale, and older comparisons stop being valid.