From Victoria University, Melbourne, Prof Wu is the guest of the New Zealand Educational Institute (NZEI) and is visiting schools and holding seminars for school board members and parents on the dangers of relying solely on National Standards testing as a judge of a school's performance.
"We need to look at education more broadly than just students' academic results."
Sandra Aikin, the NZEI senior officer teacher learning, said the union was concerned data, particularly relating to National Standards in primary schools, could be misinterpreted by the public if published.
Prof Wu said governments in many countries, including Australia and Britain, published results from national testing in the name of transparency and accountability.
However, she believed using those results to make that judgement was invalid as the data was neither consistent nor reliable.
In Australia, the data was publicly available on a website and was used by parents to choose a school or to question a school's performance.
"The big issue is the inferences people draw from the results are invalid. Whether a school is operating effectively or not, it is not valid to make those inferences."
In Australia, it had led to concerns about teachers teaching a curriculum solely focused on testing and about schools restricting lower-performing pupils on test days.
The reason for this was that there were many factors involved, other than just the performance of teachers, she said.
"There is student motivation and interest, family background and support. Teachers and the school are not all the picture. We need to take into account all the factors."
While the general perception was that large variations within pupil performance were a bad thing, internationally variation was considered to be positive and far more equitable.
Judging teacher performance should be based on more qualitative feedback from parents, colleagues and principals, Prof Wu said.
