I don't think the issue of whether blinkers may appear to improve performance has ever been questioned. It has always been about how does a punter identify which ones will appear to, and which ones won't appear to.
So I thought I'd do a recheck and see if horses in form was a key ingredient. I reckon that it would be unrealistic to call a horse that finished within 2 lengths of the winner in its last start, out of form.
So I wondered why of all the horses to race in Oz from Jan 2016 through to middle of 2017, the horses that had run to within 2 lengths of the winner at their last start (and didn't get blinkers on first time) had a next start strike rate of over 14% and an ROI for a $1 win bet on Tatts of 80%. Not a small sample either of 95,000 runners.
Yet those with blinkers on first time, achieved an 11.8% strike rate and an ROI of 76% for a $1 win bet on Tatts.
It's a lot easier to pick the winners - after they've won. Trainers seem to be putting blinkers on quite a lot - even on a horse that ran close to the winner last start. And they'd have trialled them to see that improvement would be there. Back to the drawing board on that.