This code describes the reliability of the lightcurve results in the asteroid lightcurve parameters file, and takes the following values: 0 - Result later proven incorrect. This appears only on records of individual observations. 1 - Result based on fragmentary lightcurve(s), may be completely wrong. 2 - Result based on less than full coverage, so that the period may be wrong by 30 percent or so. Also, a quality of 2 is used to note results where an ambiguity exists as to the number of extrema per cycle or the number of elapsed cycles between lightcurves. Hence the result may be wrong by an integer ratio. 3 - Denotes a secure result with no ambiguity and full lightcurve coverage. 4 - In addition to full coverage, denotes that a pole position is reported. In some cases, the numerical quality code may be followed by a plus or minus sign, indicating that the reliability is judged somewhat better (+) or worse (-) than implied by an un-signed number alone. This refinement in scale has been only recently added, and not yet retroactively, so most entries don't have signs, even in some cases where they would be appropriate.