@article{10871,
  author = {Magne J{\o}rgensen},
  title = {Relative Estimation of Software Development Effort: It Matters With What and How You Compare},
  abstract = {Software development effort estimation is frequently based on comparing the effort of one task relative to that of another. We present empirical results that show how relative estimation may result in biased assessments of similarity and over-optimistic effort estimates. We observe that tasks tend to be assessed as more similar than they in reality are when compared with each other, that the similarity of two tasks depends on the direction of the comparison and that it matters whether the comparison is based on difference in work-hours or as the ratio. We use the observations and other evidence to suggest ways of improving the accuracy of relative estimation.},
  year = {2013},
  journal = {IEEE Software},
  number = {March},
  pages = {74-79},
}