Doctor how

I was interested to read the feature on professional doctorates ("Practical knowledge", 26 February). What it perhaps misses is that the range of practices across the doctoral spectrum are much wider than suggested by a comparison between "taught" professional doctorates and "research" PhDs.

Some research doctorates now incorporate a significant taught or seminar element, while there are doctorates designed for established professionals (what I have termed practitioner or work-based doctorates) that are assessed solely or principally by thesis or work output and explication. Some of the latter are even called PhDs. I agree with John Taylor when he says that doctorates have to be about creating original knowledge, but this has to give equal weight to what Gibbons et al call "mode two" or context-based knowledge as it does to discipline-based academic knowledge.

Personally, as a consultant working in a largely academic environment, I find my DProf, based on providing the intellectual leadership for a complex real-life project, tends to carry more weight than a PhD that could have been earned from a supervised research project done before I'd had any professional experience.

Stan Lester, Taunton.