The only concern I have about merit badges, over continuing education points, is that someone focussed on TDD for a month may be able to earn a merit badge for TDD, but now there's a dis-incentive for them to actually stick with it longer--they're now focused on their next badge. Maybe instead an all-around assessment is better, every time, or a "regression test" for each new badge.
The only caveat is that you need to find a way to prevent people from
specializing in just one thing. In RPGs it is usually possible to
specialize to some degree although one generally needs to address a
broad number of skills in order to complete the main quest.
Or you could just do XP the way they do it in RPGs. i.e. you always
gain X experience points for accomplishing a given task, but tasks get
progressively harder. So, there is always XP to be had for
demonstrating skill at TDD, but you demonstrate skill at TDD in
progressively harder problems. At the same time, you can gain XP for
doing problems in other areas (Continuous integration, Story-testing,
etc.) But those areas are independently progressive. e.g. if I have
solved all the TDD problems through level 10, but I haven't done any
CI problems then there are still some level one CI problems that I
could solve.
The only caveat is that you need to find a way to prevent people from
specializing in just one thing. In RPGs it is usually possible to
specialize to some degree although one generally needs to address a
broad number of skills in order to complete the main quest.
I agree, while IMO specialization is for insects, specialization can
depend on where you put your eyes. At one level we have all specialized
in "Agile" or at least so it could be said.
As a long time game player, to me decaying points smells like a dead game.
The games I play in, the points dont need to decay because they games are
still alive. If you don't keep playing, your overall rank decays as others
are still gaining more/new points.