Risk has been alluded to and discussed elsewhere in this book, but the subject is of such importance it is identified as a subject in its own right. Risk is associated with everything we do, as individuals, where even the air we breathe can potentially harm us because of pollutants and allergens, and in the workplace. In construction it is usually considered in terms of financial risk and the risks associated with safety (see 6.3 and 21.17), but many of the principles outlined here are relevant. Risk is defined by HM Treasury as ‘uncertainty of outcome, whether positive opportunity or negative outcome’. However, others believe risk should not be confused with uncertainty, arguing the former is known about and an assessment of its probable impact made, whereas uncertainty is not known about and can have either a negative or positive effect. Clearly there is a conflict of views on this matter and the reader is well advised to seek clarification when reading others’ discourses. There is a strong correlation between risk management and value engineering. The two subjects are linked together as any value management judgement can alter the risk.