I found this as a word doc. Is the private school entrance test that you refer the ISEE (also by ERB) rather than this test? The ISEE is more widely used in my area for private schools than the SSAT.
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CTP 4: Grades 2 - 11 Comprehensive Testing Program

What is CTP 4?
Developed for ERB by Educational Testing Service to serve the needs of high achieving students and schools that aspire to higher standards, CTP 4 is a rigorous test battery designed to collect basic information about student achievement. When used in conjunction with comprehensive and accessible score reporting systems, data are organized to answer the important questions of teachers, administrators, and parents about student performance in key areas of school achievement.

Program Highlights & Features
The Comprehensive Testing Program, or CTP 4, is a rigorously designed series of assessments in reading, writing, and mathematics developed to help educators collect critical educational data that answers the questions of administrators, teachers, and parents about achievement.
CTP comprises ten levels that span grades 1 through 11.

FAQ

What is the test schedule?
The test is administered once a year, in the beginning of the first semester. Since the program consists of various assessments in reading, writing, and mathematic, the testing time would be spread out evenly in 5 days so as not to affect the performance of students.

Can I order sample tests?
No, the CTP 4 is a secured test. Since the same forms of the test are used by schools each year, the security of the test is very important. The test is not allowed to be released to the public.

How should my student prepare for the CTP 4?
This test is designed as a �low-stakes� exam, the purpose of which is to test what a student knows at a given point in time, in order to identify strengths and weaknesses. It is intended to help teachers and administrators make decisions about classroom instruction. As such, there are no preparatory materials available for it. This makes the test a more accurate reflection of the student�s knowledge, and makes it a better diagnostic tool

Does ERB construct the test?
CTP 4 was developed for ERB by the Educational Testing Service (ETS) in Princeton, New Jersey.

What kind of a test is CTP 4?
CTP 4 is not one test, but a battery consisting of a series of multiple-choice and open-ended question tests administered to groups of students over the course of several days, either in the spring or the fall. CTP 4 has 10 levels; a different level is used with each grade from 1 through 11. Students in the early grades take the test under untimed conditions and mark their answers in the test booklet. Students in the middle and upper grades take CTP 4 under timed conditions and mark their answers on a separate answer sheet. The time limits are generous, and all but a few students are able to complete the test in the time allowed. There is also an option for schools to include open-ended reading comprehension and mathematics questions in the test that provides for full, partial, or no credit.

What does the test measure?
All 10 levels of CTP 4 include achievement tests that measure what the student has learned in the areas of reading and mathematics. In addition, levels 1 and 2 test word analysis and listening skills. Beginning with level 3 (introduced in the spring of grade 3) there are also tests that measure verbal reasoning, quantitative reasoning, certain kinds of writing skills, and vocabulary.

Why is it necessary to have two reasoning tests in addition to the achievement tests?
In general, achievement tests, such as vocabulary, reading comprehension, and mathematics, measure mastery of skills and knowledge acquired directly from instruction in the classroom. Questions in the reasoning tests, intended to describe the student�s facility with subtle, abstract relationships expressed in words or numbers, yield measures of his or her ability to recognize logical relationships in unfamiliar contexts. Having both reasoning and achievement tests in the same battery enables the school to compare the results as a guide in working with individual students. Taken together, these scores help determine if a student is working up to potential or falling behind.

How accurate are the scores on CTP 4?
The scores on CTP 4 are more than accurate enough to be useful, but no test measures perfectly. Test scores are subject to error in part because many factors affect a student�s test performance, including motivation, energy, level of concentration, and understanding of directions. Moreover, the test questions are merely samples of all the questions that might be asked about a particular subject.
Accordingly, several consecutive years of test results usually provide a better estimate of a student�s knowledge and abilities than the scores obtained in any one year. The CTP 4 provides schools with data to access patterns or trends in student achievement within and across grades.

Is CTP 4 fair to all students, or are some at a disadvantage because of race or gender?
Fairness is something that was given careful attention in the development of CTP 4. Editors and others specially trained to identify bias in text or illustrations reviewed each CTP 4 question to ensure that it would not offend or be unfair to members of minority groups or either gender. In addition, statistical tests were performed to determine for each question whether significant differences existed between the performance of girls and boys. Any questions that were flagged as a result of these tests were again reviewed and, when necessary, changed before CTP 4 was released for use.

What if I have trouble understanding reports that are sent home?
Many of the score reports for parents, teachers, and administrators have been redesigned to make them easier to read and understand. We believe that the CTP 4 parent reports are especially good in this respect. But even so, we strongly urge parents to meet with school personnel. They will be pleased to assist you in interpreting test results. A school conference affords the best means of learning how your son or daughter is doing in school, and how you may be able to help him or her do even better.

Fee
The test is compulsory for every student in the bilingual department. Certain fee are collected from the students to cover the cost of scoring service. The fee is estimated to be less than US$ 20 dollars. Lower level students are expected to pay more since the test booklets for the levels are consumable.

Reference:
Educational Records Bureau, website: http://www.erbtest.org/