Another year, another set of rankings from U.S. News & World Report — the 2018 America’s Best High Schools.

Sigh.

What does U.S. News think “best” means? According to the magazine’s methodology for the list, the answer mostly involves standardized test scores and graduation rates. Never mind that the former are limited in what they tell us about a school, and the latter are, and have repeatedly been, easily fudged in one way or another.

For 2018, U.S. News gave charter schools — which are publicly funded but privately operated — seven of the top 10 spots, including the top three, which are part of Arizona’s BASIS charter network.

Here’s the list:

1. BASIS Scottsdale, Ariz.
2. BASIS Chandler, Ariz.
3. BASIS Oro Valley, Ariz.
4. BASIS Tucson North, Ariz.
5. BASIS Flagstaff, Ariz.
6. Meridian School, Round Rock, Tex.
7. International Academy of Macomb, Clinton Township, Mich.
8. BASIS Peoria, Ariz.
9. Baccalaureate School for Global Education, New York
10. Thomas Jefferson High School for Science and Technology, Alexandria

Seven of the top 10 are charter schools (BASIS schools plus Meridian), which is delighting charter school advocates who are reveling in the news during 2018 National Charter Schools Week — so declared by President Trump.

But what do these lists really tell us — and what don’t they tell us about these schools?

The new high school rankings don’t talk about why comparing traditional public schools to charters is a problem.

Traditional public and charter schools don’t operate the same way. Charters operate with different rules than public districts. They don’t have to be transparent to the public, and in many places they are run by for-profit companies. The BASIS charter network — the one with six Arizona schools in the ranking’s top 10 — is a nonprofit but is operated by a for-profit company. And that company is owned by the people who started the schools in 1998. There are 20 BASIS charter schools in Arizona and several others elsewhere, including one in D.C.

[The mess in Arizona’s charter school sector]

Nationally, the highest-performing charter schools often have high attrition rates and fewer English-language learners and students with disabilities than do traditional school districts. In 2015-2016, 1.2 percent of the students at the BASIS schools in Arizona had a learning disability, compared with 11.3 percent of students statewide, according to this piece about the charter network.

[What the public isn’t told about high-performing charter schools in Arizona]

Charter school management organizations often spend a good deal of money to market and recruit students. Charters can control the number of students they accept, which traditional public schools can’t.

The Arizona Republic reported in this article that BASIS schools get more in basic funding than traditional public schools, but they pay teachers much less and ask parents to make donations. The paper said it had obtained records showing that BASIS Scottsdale asks parents to contribute at least $1,500 per child each year — even though charter schools are tuition-free by design — to subsidize teacher pay.

The network was started in 1998 by two economists, Michael and Olga Block, who wanted to challenge students with Advanced Placement-focused curriculum. All high school students are required to take half-a-dozen Advanced Placement tests — a requirement that marries well with rankings that depend in part on student AP participation. The Blocks have alsoopened five private schools — in California, New York and Virginia — with the same kind of academic profile but with a high tuition. At the Brooklyn BASIS Independent School, for example, tuition for 2018-19 will be$28,800 for pre-kindergarten and $30,200 for K-12.

The Republic reported that the Blocks own a private company called BASIS.ed, which provides the educational services at BASIS schools. The Republic said that “according to an agreement between BASIS Schools and BASIS.ed, the Blocks’ private firm keeps 11.75 percent of all school revenues — state, federal and local tax dollars — for management fees.”

Noting that the Blocks “made a $1.68 million downpayment on an $8.4 million condominium in New York City” last December, the Republic reported on a letter sent to BASIS parents from two executives at BASIS.ed, Peter Bezanson and Craig Barrett. The letter said, according to the newspaper, that the Blocks had put “their heart and soul” and their own money into the schools and to “claim that they should not profit from their life’s work is unkind and, frankly, un-American.”

That’s right: They labeled as un-American those who criticize people who are getting rich from publicly funded schools. But putting that whopper aside, the notion that it is fair to rank these schools with traditional public schools is nonsensical.

So here’s how U.S. News decided that BASIS schools in Arizona deserved top honors in its 2018 high school rankings:

• Step 1: The first step determined whether each school’s students were performing better than statistically expected for students in that state.

U.S. News started by looking at reading and math results for all students on each state’s high school proficiency tests. U.S. News then factored in the percentages of economically disadvantaged students — who tend to score lower — enrolled at the schools to identify schools performing much better than statistical expectations. To pass Step 1, high schools’ performance had to be one-third of one standard deviation above the average. …

Step 2: For schools passing the first step, Step 2 assessed whether their historically underserved students — black, Hispanic and low-income — performed at or better than the state average for historically underserved students. . . .

• Step 3: For schools passing the first and second step, Step 3 required schools to meet or surpass a benchmark for their graduation rate. This is the third year U.S. News has included this step. …

• Step 4: Schools that made it through the first three steps became eligible to be judged nationally on the final step — college-readiness performance — using Advanced Placement and International Baccalaureate test data as the benchmark for success. AP is a College Board program and IB is an International Baccalaureate (IB) program; both offer college-level courses at high schools across the country. …

This fourth step measured which schools produced the best college-level achievement for the highest percentages of their students. This was done by computing a College Readiness Index based on the school’s AP and IB participation rate — the number of 12th-grade students in the 2015-2016 academic year who took at least one AP or IB test before or during their senior year, divided by the total number of 12th-graders at the school — and how well the students performed on those tests.