Effect of 5th grade on 4th graders

Mike the Mad Biologist [that’s his name for himself] sees an apparent wee flaw in the way some educators [as they call themselves] evaluate things. M the MB writes:

One of the supposed key innovations in educational ‘reform’ is the adoption of value added testing. Basically, students are tested at the start of the school year (or at the end of the previous year) and then at the end of the year…. what I want to discuss is a very serious flaw–what I would call fatal–with value added testing that stems from a paper by Jesse Rothstein (pdf).

[That paper says:] “…these models indicate large “effects” of 5th grade teachers on 4th grade test score gains” …

If the sentence in boldtype seems problematic, you’re right: it is.