A key element of any faculty job application is the applicant's Research Plan, the document that search committees use to get a sense of what she might do in her new lab, and her ability to argue coherently for the importance and feasibility of her work. The Research Plan is a forward-looking precis of future research directions built on the foundation of what the applicant has done in her present position (generally post-doctoral).
It is absolutely essential to understand that what you present to search committees as your Research Plan is not necessarily the same as your actual plan for future research. In fact, the two have very different purposes. The purpose of the former is to convince those who control the resources you need to pursue your research to allocate it to you. The purpose of the latter is to guide your research once you have secured those resources.
It is also essential to recognize that everyone involved in the process of assessing Research Plans understands the usefulness of this distinction, as will be explained in detailed below. Employing this conventional fiction that everyone involved is aware of is not lying. And failure to employ it puts the applicant at a severe disadvantage in competing for an extremely limited number of available positions.
This may not have mattered at an earlier time, when competition for faculty positions in the biomedical sciences was much less stringent and any gibbering dumbfuck with a PhD could secure a tenure-track faculty position. But nowadays--with funding very tight and vast numbers of highly qualified applicants for every faculty position--job applicants ignore this reality at their peril.
Search committees don't worry too much about the specific content of the Research Plan in terms of exact experiments proposed, so long as it is well-written and coherent, and is built on a foundation of outstanding prior published work.
The reasoning behind this is the following: Science is so unpredictable that once a new asst prof gets in her lab, gets some people in there, and starts doing experiments, there is just no predicting what will happen and what will get interesting. So long as the person is smart, creative, resilient, and a decent manager, good stuff is likely to happen that will lead to successful grant applications and good publications.
Search committees are not terribly concerned about the actual experiments being proposed, except to the extent that they reveal something about the intelligence, creativity, and conceptual rigor of the applicant. They do care about how well the Research Plan is written and how well it is crafted, and that the experiments proposed actually make sense and are well-justified.
Search committees are really looking to identify people who seem very "scientifically nimble", brilliant, and have a vast knowledge of the literature in their field and related fields. This is because creativity is all about taking existing ideas and combining them in lots of new ways to see if anything cool happens.
Comrade PhysioProf has not done a single fucking one of the things he proposed in his Research Plan used during his successful tenure-track faculty job search. And no one is surprised or gives a single flying fuck about that fact. Everybody understands that the Research Plan is a convenient fiction, which serves a different purpose than actually guiding the next five years of a scientist's research pursuits.
(This post is based in part on a post at the old WordPress DrugMonkey blog.)