The Independent Police Complaints Commission said the way West Yorkshire Police and two others large forces dealt with allegations had improved in the last three years, but there were still areas of concern.
It followed up a critical review in 2014 which said that complaints about discrimination by officers at Yorkshire’s largest police force were “poorly handled from beginning to end”.
In its latest report on the issue, the IPCC said police forces should do more to ensure allegations of discrimination made by the public are handled in line with official guidance.
The review looked at discrimination cases in Greater Manchester, West Yorkshire and West Midlands forces completed during 2016.
It sampled 88 cases, 11 of which were complaints made by police officers or staff and 77 of which were complaints from the public.
The review found that forces were communicating better with complainants and there had been noticeable improvements in handling complaints generated from within the police forces.
But there were still concerns about the way complaints from the public were dealt with, as none of those sampled were upheld and the quality of investigations and reports was unsatisfactory in two-thirds of cases examined.
Failings, which the IPCC says are common across the country, included not properly assessing the seriousness of the allegation, not asking probing questions, and not seeking comparator evidence where relevant.
Dame Anne Owers, chairwoman of the IPCC, said: “It is heartening to see that there have been some improvements in the handling of discrimination allegations.
“However, this review shows that there is still a way to go before forces can be confident that they are dealing effectively with discrimination complaints that come from the public.
“We have made a number of recommendations based on our findings, which I hope will assist all forces in an area that is particularly important for public and community confidence.”
Det Chief Superintendent Julie Sykes, Head of Professional Standards at West Yorkshire Police, said: “The IPCC identified positive practice in West Yorkshire, including good recording of complaints and issues being dealt with quickly when raised, early and regular contact with complainants and a pleasing range of protected characteristics being recorded.
“In terms of other good practice, the IPCC were positive about a case where we made early engagement with an interpreter and the work we do in respect of checking comparator evidence was also highlighted positively.
“Although there are some further areas for improvement, the picture is much improved since the last inspection. We remain committed to a programme of continuous improvement and will review the recommendations contained in the report.”