We've found that with some work to "level-up", The Story of the World can be used as a creditable middle-school text, but Susan Wise Bauer does not recommend it as a creditable high school text.
- SOTW is written at a very elementary level – especially SOTW 1, and even SOTW 2. It is intended to understood by 6 year old children. The writing level itself is a bit demeaning to a high-school age student.
- The elementary nature of the content could convey to a high school student that history is pretty banal.
- The content itself is appropriate for an elementary level of understanding. Using some additional "level-up" techniques and approaches, the content can be useful for middle school students who move beyond hearing the basic story (the content) and start to make connections among the events, people, and situations of each historical period. You can learn more about "leveling up" here. The high school student should be expressing opinions about historical events...but there isn't enough "meat on the bones" in the SOTW series for them to be able to do this.
Susan Wise Bauer's upper level History of the ___ World series is appropriate for some (but not all) high school students. In The Well-Trained Mind, Susan Wise Bauer makes some recommendations for high school history sequence and resources. TWTM was published in 2016, and the recommendations still stand; Dr. Bauer says she still has not run across any better recommendations than these.
Other lines to pursue: