A checklist for parents choosing childcare for their children has warned not to rely on Ofsted when identifying childcare quality.
The guidelines for England, published on Tuesday by the Daycare Trust, claim the inspection watchdog's grading system is "too broad" to provide a detailed measure of quality in childcare.
The research, funded by the Nuffield Foundation and undertaken alongside Oxford University, compared Ofsted inspections with other quality assessments such as the Early Childhood Environment Rating Scale (ECERS). Focus groups were also conducted in order to explore how the different measures are understood by parents, childcare providers and local authorities.
Sandra Mathers, lead researcher at Oxford's education department said: "Ofsted grades cannot necessarily be relied upon as a complete measure of quality, and may need to be completed by other measures."
Some establishments judged by Ofsted as "outstanding" were rated lower on the ECERS and Infant Toddler Environment Rating Scale (ITERS), according to the research. The difference in ratings could have implications on funding as the Ofsted ratings are currently used by local authorities to determine which nurseries and pre-schools receive financial help.
The research found most parents felt Ofsted reports lacked the information they need to make an informed decision about choosing the right childcare establishment.
Anand Shukla, Chief Executive of Daycare Trust, said: "There is overwhelming evidence that investing in high quality childcare in the formative years of a child's life can make the biggest difference to their life chances, but as this research proves parents are not currently equipped to make informed choices on quality."
She added given the high cost of childcare, parents "deserve access to comprehensive information" in order to exercise an informed choice.
A spokeswoman for Ofsted said parents should look at a range of information - including inspection reports.
"This report is timely as it comes during our consultation on proposals for changes to inspection from September 2012.
"Those proposals already cover a number of issues raised in this report particularly about making reports easier to understand and more accessible to parents."