The fossil record is incomplete. A particular species may not have been preserved for a variety of reasons. It then becomes difficult to interpret many patterns in the fossil record because they may represent real evolutionary change or they may simply reflect the incompleteness of the fossil record. Paleontologists have long been able to qualitatively document many causes of incompleteness of the fossil record. Now, they are able to use computers to quantitatively simulate processes of evolution, ecology, fossilization, and sediment accumulation as a means of more confidently interpreting the actual fossil record. These models have revealed that incomplete preservation not only can mask patterns of evolution but can create the impression of evolutionary patterns where none exist. Paleontologists can also use these models to devise new ways of avoiding problems of incompleteness when interpreting the fossil record.