Broad-fields design is in response to one of the major weaknesses of subject-centered design. Recall, that one concern with subject-centered design was a lack of integration. In other words, subject-centered design is considered by many to be to compartmentalized. The students do not see the connections between subjects. This lead to a curriculum design that was interdisciplinary in its approach
To deal with this fragmentation of knowledge, broad-field designers try to collapse subjects with similar content into a larger umbrella subject. Two of the best examples from would be Social Studies and Language Arts.
Social studies is the umbrella term for a mixture of economics, geography, history, sociology, and political science. Language Arts is the umbrella subject for grammar, literature, composition, and linguistics. The subjects that were combined have much in common and it was not a huge leap to merge them. For example, composition and spelling have much in common and they need each other as do history and political science.
Broad-field design is most common at the K-12 level and every teacher has encounter this design. One concern with this design is depth. By combining so many subjects, the students get a shallow amount of knowledge in comparison to the deeper content of a single-subject. Despite this drawback the principle to remember is that the needs of the students is what determines the appropriateness of the design.