[nige1]

 VixTD, on 2013-October-03, 07:04, said:

The board was played in a spade contract nine times out of a total of sixty-one.

North played in spades six times. Results were 1♠=, 4♠-2, 4♠X-2 (twice), 4♠X-3 and 4♠X-5, so it's certainly possible to get a better score playing in 4♠.

Interestingly West did rather better when allowed to play in the spade game, making on the three occasions ten, eleven and twelve tricks. One of these was on off-duty director. (I suspect these were errors in score input.)

Thank you vixtd. Again I maintain that evidence from actual results at other tables is likely to be relevant (e.g. when weighting scores) and should be investigated if conveniently available.