Creation Science starts with the assumption that God created the universe. Like naturalism it is purely philosophical assumption. It is essentially science based on the Bible.
It may come as a surprise but Creationists and Evolutionists have the same evidence, but different interpretations. The key is that Evolutionists dismiss the Bible as a collection myths or at best a mixture of myths and history; while Creationists work from the the view point the Bible contains real history starting from Genesis 1:1.
Creationists see the Bible as an historical Document. That is events described in the Bible are real historical events. When possible historical documents are the best way to study the past, and the Bible is the best preserved ancient historical document known
So Creation Science can be defined as the study of history and the physical sciences in light of the Bible. The key is not confusing scientific evidence with a particular interpretation.
Furthermore, God, the Bible, and the basic concepts of Creation as found in the Bible are the assumptions that form the foundation for the development of scientific theories. Together, God, the Bible, and Creation form the foundational assumptions of a theoretical system for interpreting data. The fact is that if the same data is interpreted by a different theoretical system the interpretation may be different.