The idea of traditional assessments is that all students take basically the same examination as everybody else. Each student is then awarded a grade based on how well she performed on a test. This makes it easier for school and governmental bodies to assess which schools are improving and which are struggling. If all students were taking different tests, there is no way of telling if a school is doing better because an exam is easier or because they have a better teacher.
Standardized tests mean students from inner-city public schools take the same examinations as private school pupils. The idea is that when students apply to colleges or for jobs it is easier for an assessor to work out who is better suited without having to make a socioeconomic determination. In theory this is supposed to reduce any deliberate or accidental racism, sexism or other discrimination.
The traditional exam as a test was devised not only to assess students on knowledge of the subject but to see how they react under pressure. Although in a work environment, time and word limits may not be as strict, learning to work under these conditions is important. An alternative assessment may be a determination made over an entire year of schoolwork where the student may not have been put under time limitations at any point.
End of year exams are cheap to produce and mark as every student takes basically the same exam. Alternative testing may be more expensive both in terms of marking and equipment as there are more elements to assess and nontraditional education methods can be used. It is important to remember this may not always be true; it depends entirely on the subject being taught and the assessment methods used.
Current employers took the traditional assessments when they were at school and may not understand what exactly students have learned at school if alternative tests are employed. This may mean a student who was taught, through no fault of his own, by alternative methods may stand less of a chance of getting a job than somebody who took exams.