U

uncertainty, expressing, 251–255. See also accuracy of estimates; accuracy of estimation method

underestimation, advantages of, 21–24

unfamiliar environment, 247

unforeseen events, 12

unfounded optimism, 46, 107–108

avoiding with historical data, 93

units of time estimates, 255

unstable project requirements, 42, 247

requirements omitted from estimates, 44–46, 110

software to account for, 160

unwarranted precision, 51–52

urgency, instilling sense of, 22

usefulness of estimates, need for, 13

User Interface Design Complete phase, 35, 39. See also Cone of Uncertainty

iterative development, 40–41