States and districts considering the use of teacher portfolios as the means for evaluating the quality of teachers may want to take a look at a study this week in Education Policy Analysis Archives. Authors Judy Wilkerson and Steven Lang expose the essentially insurmountable legal obstacles that make portfolios not just an impractical but an irresponsible choice for "high-stakes" purposes--such as whether or not a teacher should be certified or get a raise. They don't tiptoe around their conclusions, declaring that portfolios are invalid and unreliable unless districts insist on standardizing the contents of the portfolio as well as the evaluation process. Since the popularity of portfolios represents an insurgence of sorts against the use of standardized measures of evaluation, this advice may not be welcomed.

In what may be the most interesting part of the paper, Wilkerson and Lang delve into the legal implications of a negative evaluation that is based on a scientifically invalid measure such as a portfolio. Wilkerson and Lang convincingly show how portfolios undercut standards of research methodology and make licensure laws unclear which can only lead to a proliferation of lawsuits.