Argument I make in the paper is that NI failed to converge with the worst performing regions of GB 1920-1972 (it would do this in early 2000s, but I don't go into this) & devolved financial settlement was a barrier to this convergence (other stuff mattered too eg. declining staple industries)

I would counter the idea that geographic peripherality was main reason for NI underpeforming. Access to ports & GB market, & growth of large export industries during 19th century run counter to that, plus study of extra transport costs in 1980s showed these were very minor relative to GB regions

We like to be different