"slow rate of progress" is correct and usable in written English.
You can use it when you need to describe how something is progressing at a very gradual rate. For example, "Despite our best efforts, we have had to accept a slow rate of progress with the project."
Karon Monaghan said: "Given the slow rate of progress towards a diverse judiciary, firmer measures are now required, including quotas.
Some of the agencies originally involved in GARDIT have become impatient with the slow rate of progress.
Radical Shia cleric Moqtada al-Sadr leads a mass demonstration in Baghdad in protest at government corruption and the slow rate of progress in delivering on promised reforms.
Or perhaps the drudgery and routine of writing, its glacially slow rate of progress, its failures and frustrations, were just too much on my own mind..
Industry and the government have been frustrated at the slow rate of progress on exploratory fracking for shale gas and oil in the UK after David Cameron said last year that the government would "going all out for shale".
France's top climate ambassador has said she is very concerned at the slow rate of progress on a negotiating text that will form the basis of a new international deal on global warming in Paris later this year.
2 Thus, a concrete level of goal/action identification may be expected to be more adaptive when there is a slower rate of progress than expected on personally relevant goals, which may be signalled by negative affect and/or negative cognition.
Sub-Saharan Africa has the highest stillbirth rates and the slowest rates of progress worldwide.
These three countries also have the most births and have exhibited the slowest rates of progress in reducing deaths.
Unfortunately, this slow rate of investment does not ensure rapid progress in preventing heat-related mortality.
Remove foreign postdocs from the nation's labs and postdoc pay would zoom... at the cost of short-term chaos and a long-term slower rate of scientific progress.
