Z-Score Inventor Says S.B. Distorting Facts

By Indika Sri Aravinda, SundayLeader
The inventor of the Z-score Professor R.O. Thattil says Higher Education Minister S.B. Dissanayake had distorted facts about him to Parliament last week.
Professor Thattil, who had also received death threats last week, said in a letter to UNP MP Dr. Jayalath Jayawardena, that he is not motivated by politics nor is he operating against the government.
Dr. Jayawardena had asked Professor Thattil to clarify some allegations made by the Minister in Parliament.
Dissanayake told Parliament last week that the Z-score was a geometric formula and not one that was invented by Thattil.
He also claimed that the Professor had once contradicted the Z-score method.
“This is a complete distortion of facts.  What really happened was that I submitted a document in a court case with respect to rounding off errors.
In that document I stated that the Z scores received for each subject, should not be rounded off at the second decimal place before averaging the Z scores of the different subjects of a given student.  The rounding off error can go up to 0.005 (i.e. a change in the 3rd decimal place) in the final Z score.  This value is decisive at the cut off where entry to different streams are made.  For example a Z score 1.251 will be rounded to 1.25 while a score of 1.255 in rounded to 1.26.  Why round off intermediate values, when the computer can keep a large number of decimal places. How can I go against the Z score scaling technique which I advocated more than a decade ago?  I am sure the committee appointed by the President must have seen this document but never mentioned it in their report,” Professor Thattil said in his letter to Dr. Jayawardena.
He also rejected allegations of him being involved in malpractices.