A well casing is cemented in a well bore in a subterranean formation by pumping cement slurry down into the well casing so that the cement slurry flows up into an annulus surrounding the well casing. While pumping the cement slurry, the position of the top of the cement slurry in the annulus is sensed, and the rise of the sensed position of the top of the cement slurry in the annulus is recorded as a function of time. The recording is analyzed to evaluate the cement job. For example, the analysis may indicate a problem addressed by adjusting a cement plan for a future cement job, and the analysis may indicate a need to repair a location of the set cement by perforating the well casing at the location to be repaired, and pumping cement slurry down the well casing to fill the location to be repaired.