NHS England has been criticised over a decision not to publish key weekly data showing how NHS hospitals are performing over winter.
Experts said the move could hamper the way NHS trusts operate, while the public will also be unable to scrutinise the figures.
NHS England has decided to no longer publish weekly data on how well hospitals are performing against its target of treating or admitting patients within four hours.
Official figures published monthly up until September show that the target has largely been missed for the last year.
It will also not publish weekly figures on the number of ambulances queuing outside A&E departments, cancelled operations or delayed transfers of care for patients, as it has done in previous winters.
Instead, the figures will be published monthly, with a six-week time delay.
NHS England said it wanted to smooth out "misleading" fluctuations in the figures.
But Nigel Edwards, chief executive of the Nuffield Trust, said the move could fail to highlight areas where the NHS is under excessive pressure.
Last year, Labour accused Health Secretary Jeremy Hunt of enforcing a "news blackout" by not publishing weekly A&E figures over the Christmas holidays.
Mr Edwards said: "All the indications from the most recent set of performance statistics in September were that the health service is heading for a tough winter, with the figures showing that the four hour waiting time in A&E was not met again and that delayed transfers of care days had increased by almost 10,000 in a year.
"It's important for individual trusts to be able to check quickly whether their performance is out of step with that of others, and for areas of the system where excessive pressure is being felt to become clear quickly.
"I am worried that only publishing figures monthly on indicators like waits in A&E and cancelled operations won't provide this clarity quickly enough".
An NHS England spokesman said there was a desire to reduce the burden on NHS trusts over what data should be supplied weekly.
He said: "As previously announced, we will be publishing on a monthly basis a full and comprehensive set of data on NHS performance for the public throughout the year, including this winter.
"This will include the normal measures such as the four-hour waiting standard and delays in transferring patients. The advantage is that doing this gives people a complete picture while also smoothing out week-to-week fluctuations which can be misleading.
"In addition, during the coldest weeks of winter, we will be collecting on a weekly basis some operational data, while seeking to minimise the bureaucratic burden on frontline hospitals and GPs, and this will also be published on a weekly basis.
"England is the only one of the home countries that does a bespoke winter publication."
Figures from over 40 NHS trusts, published last week by the Royal College of Emergency Medicine (RCEM), showed 88% of A&E patients over the previous seven weeks were treated or admitted within four hours, well below the 95% target.
The A&E target is widely regarded as a key measure of how the NHS is performing.
The report found that hospitals are also experiencing major problems discharging patients who are medically fit to go home.
In some places, around a fifth of hospital beds are occupied by patients who cannot leave - so-called "bed blockers" - because there is not the right support in the community for them.
Dr Clifford Mann, president of the RCEM, said without weekly figures on these important areas trusts would have a "lack of good data".
Dr Mann referenced a Commons health committee report from 2013 that called for clearer information to better understand the urgent and emergency care system and where pressures are felt.
He said without this information the system will "fly blind".
He told the Health Service Journal (HSJ): "It seems as though somebody has decided to glaze over the windscreen."
He said the data was "very useful" to make "meaningful comparisons", as well as showing trusts if they were an outlier for poor performance or if others were similarly struggling.
He compared the delay in publishing the data to telling a patient their temperature reading six weeks after the event and said losing timely data was "greatly to be regretted".