Although the NHS looks like a single organisation to those on the outside, once you enter a "pathway" of care you realise that your journey takes you through a series of gardens, sometimes using gates, sometimes jumping fences I order to access the next stage.
Measuring and improving performance across this system is a matter of luck.
Luck in that if you can find a metric that is agreeable across the gardens you will be lucky to find it being measured in the same style in any garden, if at all in some. Taking the metric back to basics is a hope, did this event happen to this patient?- yes or no, means that data finite ones become less troublesome.
So looking around in healthcare why do we have so few National metrics?
Sweden, arguably one of the best performing healthcare systems has a series of national registers, which drive a metric based system.
The NHS has an excellent QOF system, but only in primary care. This system takes a cohort of patients and measures the outcomes of treatment. If QOF extended through the garden of primary care into secondary care we would know now whether all patients receive the right treatment, at the right time in the right place.

At present the best we can do is stitch together a series of indicators and cross our fingers.