A government-ordered review of Indigenous deaths in custody is “misleadingly positive”, “has the potential to misinform policy” and is “largely worthless”, a group of leading Indigenous and social academics has said.

In an open letter published by the Centre for Aboriginal Economic Policy Research at the Australian National University on Thursday, 32 academics and one institution – the Jumbunna Institute for Indigenous Education and Research – wrote that a recent review of government responses to the 1991 royal commission into Aboriginal deaths in custody hid the lack of action by governments and misrepresented the risk that remained for Indigenous people taken into custody.

“Overall, the scope and methodology of the review enable governments to hide behind the veneer of simply having introduced policies and programs which it claims have addressed [royal commission] recommendations, rather than come to terms with the real-world impacts of these policies or programs, or their overall approach to Indigenous affairs and Indigenous people in the criminal justice system,” they wrote.

They said that the review, which cost $350,000, was “of such poor quality as to render its findings largely worthless”.

Deloitte Access Economics was commissioned by the Indigenous affairs minister, Nigel Scullion, to report on the level to which Australian governments had implemented the 338 recommendations made by the royal commission into Aboriginal deaths in custody (RCIADIC).

The report was released in October and was quickly branded “abysmal” by the Labor senator Pat Dodson, who was one of five commissioners who presided over the five-year inquiry, and called a “whitewash” by Change the Record, the peak national body campaigning to reduce Indigenous incarceration.

The review found that 64% of recommendations were fully implemented in all relevant jurisdictions, 14% were mostly implemented, 16% were partly implemented and 6% were not implemented at all.

But the open letter, co-authored by Prof Tamara Walsh from the University of Queensland, Dr Kirrily Jordan and Dr Francis Markham from ANU, and associate professor Thalia Anthony from the University of Technology Sydney, said those findings were “questionable” and “substantially overstate the progress made towards implementing the RCIADIC recommendations”.

They compared it to a review of the cashless welfare card trial, which was also heavily criticised by academics as being seriously flawed.

They added that some of the policy changes listed by Deloitte as having fulfilled a royal commission recommendation had since been overturned, while others were not in keeping with the full intention of the recommendations.

The Deloitte review said the recommendation that offensive language be decriminalised in all jurisdictions was “partially or fully implemented” despite the use of offensive language remaining an offence in all Australian jurisdictions.

A recommendation that states do away with the practice of automatically jailing people for unpaid fines was also listed as partially or fully implemented despite unpaid fines remaining automatic grounds for imprisonment in Western Australia and Queensland. Yamatji woman Ms Dhu was jailed for unpaid fines when she died in custody in 2014.

Recommendations that arrest be a sanction of last resort were declared fully or partially implemented, despite measures like paperless arrest laws in the Northern Territory, and recommendations concerning the use of bail were also described as partially or fully implemented, despite most jurisdictions toughening bail laws in recent years causing a significant growth in the number of prisoners on remand.

More than half of the cases examined by Guardian Australia in Deaths Inside, an investigation of 10 years of Aboriginal deaths in custody, concerned the death of a person who was on remand or had not been formally arrested.

A recommendation that policy be based on principles of self-determination was found in the Deloitte review to be fully implemented across all jurisdictions, which the academic response said was a “fundamental misinterpretation of the nature of self-determination”.

The group has called on the government to develop national independent monitoring of efforts to implement the recommendations.