We include ratings for those vendors for which we received at least 50 responses on our latest Service & Reliability survey of 17,000 PC Magazine subscribers. These results reflect readers' experience with desktop PCs from a given vendor.

We analyzed the data using a t-test, a standard procedure for identifying differences from the average that are significant at the 95 percent confidence level. For further details, see our July 1996 issue.

The reliability rating is a measure of respondents' satisfaction with the reliability of the vendor's desktops in use over the past two years.

The repair rating is a measure of respondents' satisfaction with the repair service provided by the vendor for PCs in use over the past two years.

The technical support rating is a measure of respondents' satisfaction with the vendor's support for machines in use over the past two years.

The units needing repair rating is a measure of the proportion of desktops that the respondents indicated needed repair during the past year. Better than average means that the incidence of needed repairs is significantly lower than average.