[sajforbes]

It's worth mentioning that just because something tops a list of conditions, doesn't mean money/effort is best spent there. The true measure is expected benefit per $ spent. Some conditions prove particularly resistant to research efforts, while others might be comparatively cheap to cure or alleviate. In those cases you are better off focusing on the 'easy wins' and moving to the more difficult problems once the biggest and fastest gains have been made with the comparatively easier conditions.