After having been absent from the Board for a while learning Welsh (!) I re-started my browsing this afternoon with Frans' very interesting fireside chat and then followed that up with a review of this link started by Petagny.
The question posed (do sector MTEFs make sense?), appears to require little in the way of an answer. In and of themselves, they make little sense for the very good reasons outlined by Petagny. The reason for their emergence (in fact and in ToR-land) is undoubtedly due in part of the misunderstanding and poor donor procedures identified by Napodano and the sloppy approach to these things identified by Mr Short. Perhaps the underlying factor in each case is the use of the term 'MTEF' by practitioners, governments and donors alike when what they really mean is 'budget reform'. In the context of budget reform, however, laying the initial building blocks for an MTEF will, in some cases, require dedicated budget reform work in a very limited number of sectors.
Way back in 2002, for example, the Government of Pakistan approached DFID to request assistance in the design and implementation of a Medium Term Budget Framework (i.e. an MTEF with a more explicit recognition of resource specification in the acronym). (It is probably little coincidence that this followed an IMF recommendation for an MTEF in Pakistan.) What followed might be described, if one were to subscribe to such a notion, as a 'sector MTEF' (in Health and Population Welfare). In practice, it was one aspect of budget reform for a particular sector. Throughout it was referred to by Government, donors and virtually all other stakeholders as an MTBF. Some five years had passed before the federal government of Pakistan began to put in place the top-down elements required of a functioning MTBF, before ceilings began to be defined across almost all ministries (for the non-development budget - in aggregate only at that time for the development spend) and before the policy and output-based budgeting approach began to be applied across (almost all) ministries. As a close observer of this process throughout, one of the things that interested me was the pre-requisite in Pakistan for some sector-based budget reform (supported by the Finance Ministry) to establish some minimum building blocks for the future development of an MTBF. Whilst the current more comprehensive approach is some distance from the approach of the initial years (and can now, much more justifiably, be referred to as an MTBF, however nascent it remains), it is hard to imagine the current achievements without the prior sector-based budget reform work having taken place. In terms of the initial years, the label 'MTBF', therefore, was most certainly inaccurate with regard to the arrangements for specifying resources and planning expenditure. It was not inaccurate, however, with regard to a longer term aim of developing an MTBF.
I have little doubt that the examples of 'sector MTEFs' (in whatever form) cited by my colleagues were of the ill-informed and or sloppy variety, but there is certainly plenty of scope for some of the early stages of MTEF design and implementation to be built upon aspects of sector budget reform. Being clear about what that reform is, is not and is intended to be is clearly important in this regard.