Are we losing too many good teachers because of a data driven education system?

It's not "data driven"
It's "lousy data driven"

http://icingonthecakeblog.weebly.co...ly-ditch-the-cargo-cult-data-for-actual-data1

Much of the progress-tracking ‘data’ which has become all too important in English education could actually be more correctly described as Cargo Cult Data. Cargo Cult Data has the appearance of real data, without having any of the requirements of statistically valid actual data from which one could reasonably draw inferences. It doesn’t pass the simple Fair Test most primary school children would recognise,