The union has told the Scottish Office: "There will be a critical problem in dealing with an older, and previously fully competent, teacher with perhaps four or five years of service left to normal retirement age. The association can support no system which does not address this issue."
It adds: "Whereas the potential for a relatively younger colleague to gain alternative employment outwith teaching may not be huge, it is certainly much reduced for those in the later years of a teaching career."
The SSTA shares the Educational Institute of Scotland's view that the General Teaching Council should enjoy a pivotal role in assessing competency across the country before councils take action.
The union says using the GTC as an independent assessor would prevent charges of prejudice against individual teachers. "Speed has to be consistent with equity and thoroughness in this regard. A proper appeal mechanism has to exist," it states.
All teachers with a perceived need to improve their skills should have training available to them and no attempt to dismiss should be made before it has been provided, the union adds. Teachers had to be given every chance to improve.