early development stage, 80
counting at, 85
education of nontechnical staff, 263
efficiency of defect removal, 242–245
effort multipliers, Cocomo II model, 66
effort, project
allocating to various activities, 233–238
collecting data on, 95, 96
comparing estimates for, 218
computing, 210
estimating, 207–219
with fuzzy logic, 138
with industry average data, 210–216
influences on, 207–208
from project size, 209–210
software for, 158
practical considerations (ideal vs. planned), 239–241
tradeoffs with scheduling, 227, 228–230
EMs (effort multipliers), Cocomo II model, 67–70
environment, programming, 65
equations
Basic Schedule Equation, the, 221
Complex Standard Deviation Formula, 122
Dutch Method's Indicative Function Point Count Formula, 203
Informal Comparison to Past Projects Formula, 223
ISBSG Effort Formula for Desktop Projects, 217
ISBSG Effort Formula for Enhancement Projects, 217
ISBSG Effort Formula for Fourth Generation Projects, 217
ISBSG Effort Formula for General Projects, 216
ISBSG Effort Formula for Mainframe Projects, 216
ISBSG Effort Formula for Mid-Range Projects, 217
ISBSG Effort Formula for New Development Projects, 217
ISBSG Effort Formula for Third Generation Projects, 217
Magnitude of Relative Error (MRE) Formula, 110
Modified Complex Standard Deviation Formula, 124
PERT Formula for Estimating Number of Components, 139
Pessimistic PERT Formula, 109
Program Evaluation and Review Technique (PERT) Formula, 109
Simple Standard Deviation Formula, 121
errors in project. See software quality
errors of estimation. See sources of estimation error
estimate accuracy. See also sources of estimation error
benefits of, 27–29
counting error. See counting
expressing uncertainty, 251–255
flow of estimates (reestimating), 171–180
chronological, 173–175
poorly estimated projects, 171
recalibrating after missed milestones, 175–179
scheduling reestimation, 177–178
well-estimated projects, 172–173
historical data and, 91–95
need for, 13
overestimation vs. underestimation, 21–24
precision vs., 51–52
reviewing. See reviews of estimates
software industry track record, 24–27
Estimate Express tool, 163
estimate influences, 55–72
diseconomies of scale, 56–61, 70
effort estimates, 208
modeling after historical data, 99
software to account for, 160
when unimportant, 60
kind of software, 61–63, 236
miscellaneous other sources, 65–70
personnel factors, 63
political, 260–263
programming language, 64–65
size. See project size
estimate precision, unwarranted, 51–52
estimate presentation styles, 249–257
assumption communication, 249–251
expressing uncertainty, 251–255
ranges, 256–257
estimate rejection, 262
estimates, communicating about, 4–6
estimates, debating, 172, 269. See also negotiation and problem solving
estimates, defined, 3–14, 173
common definitions, 9
good estimates, 9
plans vs., 4
probability statements, 6–9
working definition, 14
estimates, reviewing. See reviews of estimates
estimating models, industry differences in, 63
estimating software size. See size, project
estimation error, sources of, 33–53. See also accuracy of estimates; accuracy of estimation method
chaotic development processes, 41
Cone of Uncertainty, 35–41
reestimating throughout project, 173–175
schedule estimates and, 222
miscellaneous other sources, 52
off-the-cuff estimates, 49–51
omitted activities, 44–46
politics, 259–270
attributes of executives, 259–260
avoiding with historical data, 93–95
influences on estimates, 260–263
negotiation and problem solving, 259–260, 261, 263–270
subjectivity and bias, 47–49
unfounded optimism, 46
unstable project requirements, 42, 247
requirements omitted from estimates, 44–46, 110
software to account for, 160
unwarranted precision, 51–52
estimation flow (reestimating), 171–180
chronological, 173–175
poorly estimated projects, 171
recalibrating after missed milestones, 175–179
scheduling reestimation, 177–178
well-estimated projects, 172–173
estimation negotiation, 263–270
attributes of executives and, 259–260
estimates vs. commitments, 261
estimation politics, 259–270
attributes of executives and, 259–260
avoiding with historical data, 93–95
influences on estimates, 260–263
negotiation and problem solving, 263–270
attributes of executives and, 259–260
estimates vs. commitments, 261
estimation skill, testing, 15–19, 273
estimation software, 157–164
calibrating, 162
computing effort with, 210
computing schedule with, 225
estimating project size with, 205
list of, 163–164
estimation techniques, 77–81, 80
by analogy, 127–133
basic approach, 127–132
effort estimates, 209–210
estimating project size, 205
estimating schedule, 223–224
obtaining detailed information, 128
size comparisons, 129
uncertainty with, 128
applicability tables, explained, 81
computation, 83–84
converting counts to estimates, 86–88
stage-gate processes, 187
counting, 84–86
computing estimates with, 86–88
function points, 200
stage-gate processes, 187
Delphi technique, 150–155
how to choose, 77–80
judgment. See expert judgment; off-the-cuff estimates
multiple approaches, using, 165–169
for effort, 218
for project size, 206
ranges, presenting, 256
for schedules, 231–232
stage-gate processes, 187
proxy-based, 135–147
fuzzy logic, 136–138, 205
standard components approach, 138–141
story points, 142–144, 205
t-shirt sizing, 145–146
events, unforeseen, 12
evolutionary delivery, 79
evolutionary prototyping, 79
executives, attributes of, 259–260
expected-case calculation, 108–109, 120
complex standard deviation formula, 122–124
by decomposition. See decomposition
simple standard deviation formula, 121–122
expert judgment, 83–84, 88–89, 105–112
comparing to actuals, 110–106
group (structured) judgment, 106–110, 149–155
estimating project size with, 205
Wideband Delphi technique, 150–155
insisting on objective criteria, 268
exploratory estimate (stage-gate processes), 184, 185, 188
exponential increases with project size. See diseconomies of scale
extending schedule to reduce effort, 228
external bias, 48
external I/O, as function points, 200
external interface files, as function points, 200
external political constraints, 260
extreme programming, 79
story points, 142–144, 205