The effectiveness of Waltham Forest’s gang prevention programme has been questioned after an independent assessment revealed shortcomings in crucial areas.

The Enough is Enough initiative has received praise at national level for work to tackle gang culture and a recent report to a council scrutiny committee claimed it was working successfully to reduce violent crime.

But an independent report commissioned by the council, which has been seen by the Guardian, claims data on the programme has not been collected efficiently enough to give a clear picture of performance.

It also said that violent crime has fallen across almost all London boroughs experiencing gang problems and caution should be applied in attributing the fall in Waltham Forest to the programme.

The report by consultants Cordis Bright, said: “The review of gang prevention programme (GPP) documentation suggests that, with the exception of enforcement related performance indicators (and these crimes statistics are not directly linked to the work of the GPP), there is very limited evidence of systematic monitoring of the impact that the GPP is having on outcomes.

“There is currently a lack of robust quantitative data that demonstrates the GPP has had a sustained positive impact on the lives of beneficiaries.”

The report recommends the council adopt a better system of collecting and analysing data in order to gauge performance, but that doing so would require a “more sophisticated” approach than is currently in place.

It was also found that data is not effectively collected in areas such as the number of referrals in the programme, the source of referrals and the outcomes of cases.

As a result it is not possible to assess the programme’s effectiveness or whether it is achieving its intended outcomes, the report found.

The council’s own report on the programme said that, as a result of the programme, rates of personal robbery, gun crimes and knife crimes had all dropped.

Cordis Bright questioned representatives of organisations involved in the programme, service providers, community members, workers and beneficiaries of the programme and their families.

The report also noted that stakeholders valued the programme as innovative and ambitious, and acknowledged that due to recruitment issues and restructuring in the council, the programme was operating in “challenging circumstances”.

A second report is due in November, followed by a final report in June.

The council has been approached for comment.