From this website, it just looks like academic progress testing, similar to NWEA's MAP testing. If that is the case, there would be no prep for it, as it's measuring what your child knows at the point they take the test.
http://erblearn.org/schools/achievement/ctp"What is CTP?
"The Comprehensive Testing Program (CTP) is a rigorous assessment of student achievement of essential standards and learning domains for grades 1-11 in English language arts and mathematics. Verbal and Quantitative Reasoning tests are included for grades 3-11. CTP is available in the traditional paper-pencil version (CTP 4) and an online version (CTP Online).
"Features and Benefits of CTP 4
(paper/pencil version)
"Provides detailed, robust and timely feedback for each student, class and school to inform instruction and learning
Offers useful data to compare student performance and growth with similar groups of achievers via national, independent, public and association norms, stanines and percentiles
"Offers assessment with accommodations in accord with IEP's
"NEW - More efficient and environmentally friendly....and stop sorting through tons of paper to find the report you need! All CTP 4 reporting is now available online so you can choose the reports you need and simply post or send them to the staff and/or parents, or print the desired reports at your school.
"NEW - No more a-la-cart ordering! Your school now has a choice to order Basic Packages or Value Packages. View the reports included in each package in the table below or click here to download the form. Simply click on a report in the below table and see a sample report!"