NEW ORLEANS  A broad education overhaul under way here has produced improvement in test scores, results released Tuesday showed, though many students are still struggling.

The number of fourth graders who passed a state promotional exam increased by 12 percentage points over the previous year, and eighth graders improved by four percentage points.

School officials also noted significant increases in the numbers of students with passing scores in the test’s various components  English, math, science, social studies and reading.

Nonetheless, more than half the students who took the test in those grades did not pass, and 60 percent of high school students got an unsatisfactory ranking in standardized English and math tests, a figure three to four times higher than the percentage throughout Louisiana.