Community colleges are mostly a mystery to education writers like me. Readers and editors rarely demand coverage of those two-year schools, even though they educate nearly half of U.S. undergraduates. But my editor has asked me to spend some time looking inside them, where the biggest policy changes involve math and English placement tests that new students must take when they enroll.

Reformers trying to cure the failure of community colleges to get many students ready for four-year colleges say the placement tests slow students down, forcing them into remedial courses that are often poorly taught if they do not score high enough. The students have to pay for remedial courses, but get no credit for them. Several Washington area two-year colleges are trying to fix this. Here is what they are doing:

At Montgomery College, entrance officials have tried an experiment giving a second chance to Montgomery County school system graduates who do not get the required scores on the SAT, ACT or Accuplacer placement tests. College officials look at their high school grades in math and English. “Students who performed at a grade B or better in certain courses are permitted to enroll directly into college-level math and English courses,” said Montgomery College spokesman Marcus S. Rosano.

All but one of the 19 students given this opportunity passed their for-credit college courses last year. Six received As and eight got Bs. Rosano said the results were so good the college plans to seek more Montgomery County high school graduates to participate.

Howard County has an even larger program that welcomes new students into for-credit English courses even though their Accuplacer scores would have previously disqualified them. The college’s spokeswoman, Elizabeth S. Homan, said this accelerated learning program, which helps them strengthen their skills while enrolled in college-level English, has been operating for several years. Last year, 242 students took an English composition course under this system. “Students achieved an 84.3 percent success rate,” Homan said.

Homan said the college has a new second-attempt placement system for students who did not score high enough on the Accuplacer math test. They take a short quiz on the elements covered by the remedial course they previously would have had to take. If they do well enough on the quiz, they can take the for-credit course.

The College of Southern Maryland has some short courses for students who miss on Accuplacer that allow them to get up to speed quickly. Bill Comey, vice president for student and instructional support, said some students who came close to the required mark on the English placement test are allowed to take a for-credit composition course that includes “intensive support services to help moderately under-prepared students succeed.” The college also is trying to buttress for-credit courses with enhancements that improve reading skills.

Frederick Community College, like Montgomery, has had success exempting local public school students from its math placement test if they receive final grades of at least B in relevant high school courses. “From July 2011 through June 2014,” spokeswoman Caroline Cole said, “this exemption was used by approximately 1,548 Frederick County public schools juniors and seniors.” She said the college and the school district found that students using the exemption “are just as likely to succeed in their first math course [at the college] as students scoring college-level on the ACCUPLACER.”

The University of the District of Columbia Community College is participating in one of the boldest local efforts to alter the placement test system, organized by the Complete College America non-profit organization, which is based in Indianapolis. It uses what is called corequisite remediation, in which most students who do poorly on Accuplacer or other placement tests are still allowed into for-credit courses. They are given remediation at the same time in a separate course, or in the for-credit course, which is lengthened so there is time for remediation.

UDC Community College chief executive officer Dianna G. Phillips said the corequisite remediation approach will be tried with some students this fall, with plans to implement it fully in 2016.

Officials at Prince George’s Community College did not respond to my requests for information.

The Maryland and D.C. community college efforts to ease the grip of placement tests are mostly new and need more research. In Virginia, on the other had, all of the community colleges have been engaged in similar reform efforts for several years, the subject of my next column.