He says he could write a fine research report, and use all kinds of statistics and evidence, but the purpose of study is not merely to do research. If you really want to know how research results can be put to use, and how to resolve technical problems, you have to "go into the field."
他說他可以寫出一篇很好的研究報告，引用各種統計數據，但讀書的目的不只是要作研究；真正要瞭解研究結果可以怎麼用，技術性的問題如何解決，還是得到「現場」。