In North America, unified exams are typically administered to students
wishing to enter university in highly competitive fields. In some
countries, like Japan, students must write the unified exam for
entrance into any first year program. For more information on unified
exams in japan, see:
Russia uses unified state exams for entrance to higher education.
Advocates of unified tests claim poor and disadvantaged but smart
students can better compete to get into university. Prior to the
introduction of the Unified Exam in Russia, educators felt that
promising students were not able to attend university because they
lacked money or the transportation to write exams administered by each
Unified exams are also used in Malaysia, China, Singapore and Brazil.
I found a fairly one-sided article on the negatives of the Brazilian
system of University entrance unified exams:
Most of the research done in in this area in North America uses the
term 'standardized test' or 'standardized testing' rather than
'unified exam'. In my explanation, I will be using the term,
'standardized test' or standardized testing interchangeably with
unified exam. Standardized tests are exams that contain the same test
questions (or test questions randomly pulled from a pre-authenticated
bank of questions) and are administered to all students taking the
same subject matter at the same time.
In North America, standardized tests are used both as a screening tool
for entrance to higher education (colleges and universities) (MCAT,
LSAT, GRE) and as an accountability tool for school districts in the
elementary, middle school and high school years.
In countries with free post-secondary education systems, some method
is required to reduce the number of applicants to what the university
can physically hold and educate. The effect is to reduce the number
of eligible university applicants that are actually admitted to the
university. You will find this in some of the European countries.
In other cases, such as Russia, unified entrance exams have been
introduced as a means to cut through the bribery and fraud that
previously was the way that students gained entrance. The unfortunate
effect of this policy has been seen in Brazil where the students who
perform the best on the unified entrance exam are those whose parents
have had the money to send them to private schools. In Brazil, the use
of unified tests has not resulted in greater accessibility to poor or
marginalized students. (See the link above for more information on
In North America, the purpose of entrance exams like the MCAT (Medical
College Admission Test) is to predict which students will excel in
medical school. A study done by Jones (1993) found a correlation
between MCAT scores and courses in medical school that covered similar
You had asked about the pedagogical justification for not using
unified exams (or standardized tests) in the classroom.
One of the issues with standardized tests in the classroom is that
sometimes they aren't 'standardized' very well. Teachers can be
complacent or not understand how to administer the test correctly. The
testing procedure may be complex and difficult to follow. The
supervising teacher may not be well trained in the administration of
standardized tests. For a thorough article on this issue, see:
I found an article, written by a couple of psychology and education
faculty members at Rutgers University that details some of the issues
with standardized tests.
To summarize the article, some teachers will "teach to the test",
resulting in students who may do well on the test, but have a poor
grasp of the overall subject matter. Some students become very anxious
when faced with a standardized test (as opposed to other assessment
methods) and do very poorly, even though they know the material.
Standardized tests have also been used in the past to discriminate by
race and by gender, although some test creators have revised the test
(like the SAT) to eliminate certain biases.
Another article discusses additional issues with standardized tests. I
will summarize below.
Problems include the multiple-choice nature of standardized tests.
There are many type of knowledge that are difficult to assess via
multiple-choice tests. Standardized test naturally 'assume' that the
test results for the entire group of students will fall along a
bell-curve. This results in a disincentive for some students where
they feel that 'someone has to be on the bottom half of the curve'.
The incidence of cheating also increases when the accreditation and
reputation of a school is based on standardized test scores. The
article also describes alternatives to the standardized test that are
more pedagogically sound.
You also asked about the benefits to standardized tests. In my
research, I was unable to find reference to benefits to the student
via standardized tests. In most instances, the advantages seem to be
in the perceived accountability of the school system to the public. It
is felt that by using standardized tests, that the public knows which
schools are producing knowledgeable graduates and which are not. See
the link below:
In fact, the argument has been made that by publishing the
standardized test results for public schools (grouped as averages by
subject categories, not revealing individual students' marks) that
drastic improvement in teaching quality is made. Carolyn Hoxby has
argued that standardized testing is actually the cheapest way to
improve schooling because school administrators will go to great
lengths and institute many reforms and improvements to avoid being at
the bottom of the ratings list. See her article below for further
Other benefits described in the article below include the use of
aggregate test results to communicate between school districts and the
government. Governments may decide to change and improve the
curriculum taught if there is a pattern of student weakness in certain
subject areas. Some also argue that standardized tests send a message
to teachers in areas where they need to improve their teaching
(however, the flip side can become "teach to the test").
If you are interested in finding more information about how
standardized tests are created, you may want to further your search
using terms like psychometrics or psychological testing.
Thank you for your question. If you need any clarification of this
answer, please don't hesitate to ask prior to rating this answer.
"standardized test" issues problems
"standardized test" benefits