Over the past two decades, there has been a steady improvement in the quality of both bored cast-in-place and displacement types of piling. This has been brought about by a gradually increasing awareness of the ways in which defects in piles may occur, better specifications, a greater degree of supervision, and an interest by the leading piling contractors in improving methods and efficiency. The introduction of various integrity tests may also have promoted self-imposed improvements in installation techniques by piling contractors, although it should not be forgotten that certain leading piling contractors have been actively involved in the introduction and use of integrity test methods.