How can surveying reading material improve your comprehension?

Surveying is one of the reading techniques which one can use in order to quickly determine the content of a written document.
Surveying involves taking a broad look at a text by focusing on the general aspects in order to determine the relevancy and the value of the text, that is, to know whether it is worth reading or not.
Surveying helps comprehensions by bring to focus the general aspect of the text such as title and introduction. Understanding the general aspects of the text will greatly enhance one's understanding when one is reading for details.

Where is the data? ? and graph