@article{10883,
  author = {Magne J{\o}rgensen and Torleif Halkjelsvik and Barbara Kitchenham},
  title = {How Does Project Size Affect Cost Estimation Error? Statistical Artifacts and Methodological Challenges},
  abstract = {Empirical studies differ in what they report as the underlying relation between project size and percent cost overrun. As a consequence, the studies also differ in their project management recommendations. We show that studies with a project size measure based on the actual cost systematically report an increase in percent cost overrun with increased project size, whereas studies with a project size measure based on the estimated cost report a decrease or no change in percent cost overrun with increased project size. The observed pattern is, we argue, to some extent a statistical artifact caused by imperfect correlation between the estimated and the actual cost. We conclude that the previous observational studies cannot be considered as providing reliable evidence in favor of an underlying project size related cost estimation bias. The more robust evidence from controlled experiments, limited to small tasks, suggests an increase in underestimation with increased project size.},
  year = {2012},
  journal = {International Journal of Project Management},
  volume = {30},
  number = {7},
  pages = {751-862},
}