We analyzed documents with an interpretive approach.17–20 In this type of historical analysis, “the focus of attention is on meanings… . Each document [is] reviewed carefully and the ‘taken for granted’ assumptions and viewpoints of the author[s] drawn out.”21(p151) Consistent with the analytic tradition within which we were working, we specified no preanalytic conceptual schema.22–24 To develop this interpretive account, one of us (P. A. M.) reviewed all documents, and both authors reviewed selected key documents and took detailed notes. We relied on iterative reviews and discussions of documents and notes to identify common themes and clusters of meaning.