I think I am in a dead end here. I have to provide a rational on how to select the geographic location of my fieldwork. My research will take place in hospitals and general practices and will involve interviews with health professionals, managers and patients and I have picked up London area for 3 main reasons:
1) Huge variation of socio-demographic characteristics of health workers health professionals, managers and patients
2) Ease access for the researcher
3) It will be cheaper for me to do it in London than other big cities in UK. So it would be feasible to do it as my research grant could cover the associated expenses.

Do you think the aforementioned reasons could scientifically justify the rational for selecting London?

Do you happen to think of any other criteria that could influence choice

Many thanks to all of you

2 and 3 are not scientific justifications. They are pragmatic justifications, which are still valid - but related to the practicality of doing your research not the outcomes.

1 - depends on your research question. Are you relating the answers to demographic variables? If so, what ones? And are you hoping to claim that your result is universally applicable? I mean, if your question relates to access to healthcare, then claiming that interviewing in London will give answers with universal validity does not hold (cos it will be very different in the highlands of Scotland).

To ask a Q back, what is the basis on which you want to be SCIENTIFICALLY valid in an interview-based study?

it is just that I don’t think justifying the choice of the settings only on the basis of convenience to the researcher is the right approach. I was hoping that the variation of economic and sociodemgraphic characteristics within the same community could have an impact on the research question and could be related with the outcomes. The main research question is to understand the process of implementing new evidence "as it happens" into health care organisations and explore variation in practices.

what do you think? what else do you think could influence your choice of location in this particular context?
many thanks

Why just city hospitals? Your question sounds like you might benefit from seeing such implementation in a variety of settings. That doesn't have to make it very expensive necessarily though- for example there are hospitals based in smaller towns, with more rural communities, based within a reasonably short and cheap train ride from London.

as I am in a similar position (will also be doing interviews in clinics) I have some thoughts:

- Are you visiting primarily teaching hospitals? You could argue that only London has enough teaching hospitals. (Access might be easier than to other clinics)
- You could perhaps argue (f.e. on the basis of exploratory research - or just assuming) that new stuff is implemented faster/differently in London / teaching hospitals and thus to avoid too many unknown variations, you are concentrating on an area where this one factor at least should be ~ homogenous. Thus, London, or thus, teaching hospitals and continue with arguing the first point.
- Could you argue that much research is conducted in London and that you expect there might be connections between research and application, as in clinical trials? Thus differentiating London from other cities.

- You could say 'from this perspective, only the cities that have large medical research facilities as well as large numbers of teaching hospitals are in question, thus London, Cambridge, Oxford' (Just guessing here!). 'Since from these cities only London offers enough variation, London it is.'
hope that helps!

Well, I think that pragmatic justifications are good ones. I did my research in the area in which I live - I never thought about doing it elsewhere, it would have made no sense to be travelling across the country to do interviews all the time. And access is another huge factor - it is where you can get people to let you in to do the research. Are you part of a group with established contacts in hospitals etc? Cos the governance and COREC processes are sort of linked, so for me it was more about knowing I would be able to get to work with people from the region than trying to find any 'scientific' justification.

Having said that, if your research is driven by a comparision between uptake in groups socio-demographic groups, then that is find as a justification, but bear in mind you will have to be ensured of recruiting sufficiently from each variable. And it sounds as though you have quite a lot of variables already - different sorts of hospitals, primary care, possibly different professional groups (GPs, consultants in different specialities, managers). I mean, it can be hard to recruit in the NHS, and you don't want to make it harder for yourself than you have to by pinning yourself into a corner before you start with the specificity of your question.

I would like to thank you all for your time and useful ideas you offered to me.
All the best