BATON ROUGE, La. (AP) — Louisiana'spublic schools are starting a three-year shift to more rigorous testing of public school students, using a set of uniform standards designed to better prepare students for college and careers.

The transition will change what items are included in the standardized tests given to students each spring, which will change how teachers instruct their students.

Louisiana is joining 47 other states in moving to the "Common Core" standards, which were developed by states seeking to have a set of uniform benchmarks for what students should learn by graduation.

Superintendent of Education John White says they will be fully phased into Louisiana'scurriculum and testing by the 2014-15 school year.

The implications are widespread, since student performance on standardized tests is used to judge school performance and to evaluate teachers.