While research is by its nature highly unpredictable, successful research can be extraordinarily valuable. In fact, a few truly successful researchers can justify support for a large community of researchers.
Research is unpredictable because it is difficult to forecast the future or estimate the skill and stamina of individual researchers. It is hard to determine who has chosen the right problem and whether that group or person will be successful or not.
Faced with these uncertainties, a prudent research funding policy invests in more people with smaller grants in a larger number of areas than the converse. Such a policy increases the odds that some investigators will be successful. A wise funding policy will also increase the interaction between researchers, thereby seeking to encourage cross fertilization and creativity in problem solving.
It is important to note that good researchers are very aware of the objectives
of their field and need nurturing rather than direction. Should they stray
for too long from a path that appears to be directed toward the problems of
the field, this is cause for concern. However, the unpredictability of
research demands that patience and tolerance be the hallmarks of a successful
research funding policy. A research direction that may seem unpromising to
some, for example, an exploration of proof methods in the pursuit of the
P 
NP question, may eventually be very productive.
Standards must also be met. Funding should be provided to those who are thought to be most capable of doing the research. Peer evaluation works very well in this regard but there is also a need for enlightened, unilateral decision making on the part of those with funding responsibility. Variety in research funding criteria as well as in research topics reduce risk
As research fields mature, there is an increasing need to apply the fruits of research. Often the application of research results is far from simple and offers important and interesting intellectual challenges. Some researchers may wish to follow research topics as they become more applied, thereby serving the profession as well as themselves.