The friends of good handwriting worldwide may — or may not — be aware of some very large-scale research (n=2500) on speed and legibility, which is old enough that it should be replicated today.
Note the attached PDF (title page, showing citation data, and two following pages), which summarizes a VERY large-scale research study of italic and other handwriting (2500+ students, ages 7-19, in 23 schools) that was published in 1952 (62 years ago!) in a UK journal called THE SCHOOLMASTER (the organ of the UK’s National Union of Teachers, and now re-titled JOURNAL OF THE NATIONAL UNION OF TEACHERS).
The author, Percy Wood, was a government inspector of schools.
Though the article is brief enough, and well-thought-out enough, to deserve careful reading in full, the “hard” data on handwriting will be found on its last page. These data include the sample size and composition (2500+ students, ages 7 through 19, at 23 schools) along with data on the speed and legibility of writers in the various styles used.