As a conversation starter, the state-issued school report cards have been a success. Administrators and parents at schools receiving poor grades have rushed to defend the schools, and to provide a clearer picture of what is going on within those schools.

By every other measurement, however, the report cards, based on test scores, student progress and graduation rates, are a failure. Accountability is important, but the grades offer only the narrowest assessment of school performance. What they do measure serves only to confirm the correlation between poverty and low standardized test scores, and open the way for year-to-year fluctuations that make the grades misleading.

And besides the shame of a low grade, the grading system offers neither a carrot nor a stick for helping low-scoring schools address the factors underlying their performance.

No grades will be given next year, as the state moves to a new assessment test, and the future of the report card system is uncertain, since both of the candidates facing Gov. LePage in the November election have made their opposition clear. That means there is a good chance that the report cards won’t return from hiatus.

But just because this system for measuring school achievement falls short doesn’t mean that its goals aren’t worthy. The Department of Education should use the time off to find a way to more comprehensively measure performance, so that a school’s strengths can be reinforced, and its true weaknesses addressed.

The 2014 report cards, released Thursday by the Department of Education, showed that 72.8 percent of schools received a “passing” grade (at least a C), down from 80.9 percent in the first report cards, issued last May. Statewide, 93 schools were awarded a higher grade than last year, while 153 received a lower grade.

So what does that mean? All in all, not much.

Standardized test scores in math and reading provide only a snapshot of how certain students performed in those subject areas at the time the test was given. While there is value to tracking those scores, they are hardly an indication of a school’s overall effectiveness. In fact, test scores, on the whole, are more an indicator of the socioeconomic status of a school’s student body than anything else.

That analysis holds up with the 2014 report cards, just as it did with the 2013 grades. According to the Maine Education Association, 78 percent of the schools that scored failing grades in 2014 receive federal Title I funds, designated to help schools with high numbers of children in poverty. Similarly, a University of Southern Maine study showed a strong correlation between poverty rates and the schools given low grades in 2013.

And little is to be gleaned from the year-to-year changes. While the state lauded improving schools in advance of the report cards’ release, and critics of the law have pointed out the increase in failing schools, the data used are almost a year behind. The standardized tests either were given last spring, just as the first grades were given out, or early this fall, giving schools no time to implement reform.

In addition, the data are susceptible to year-to-year fluctuations, given the small sample size. The formulas used by the state accounts somewhat for this effect, but standardized test scores, SAT participation rates and graduation rates can vary enough from one class to the next to alter a school’s grade.

That means schools are being judged on only a small part of what they do, by a formula that offers no meaningful way to track improvement.

Instead, the assessment should be more thorough. It should look at additional subject areas, as well as strength of instruction and use of innovation. They should take into account the factors outside of school that put students behind, and offer the kinds of support, such as additional teacher aides and literacy support, that help close the gap.

That wouldn’t be as simple as giving a single letter grade based on a few data points. But it would be more helpful.