A Telephone-Access Biomedical Information Center

This paper examines the costs of information centers using voice-grade telephone lines to provide access to recorded messages on subjects of interest to physicians. The methods developed are applicable to the analysis of any telephone-access information system. Telephone-line rental charges constitute the major portion of costs. Sufficient lines must be available so that no more than 5 percent of peak-usage calls will be blocked; the number of lines required is obtained from queuing theory. A break-even volume of calls is calculated from the rate structure, and the appropriate mix of flat-rate and metered-rate lines determined and costed. Also examined are the sensitivities of communication costs to errors in usage estimates, variations in mean service time, and changes in the peak-hour blocking criterion. Multiple-center configurations are also investigated. Although communication costs are generally lower than for a single center, the single center has the lowest total annual operating cost, due primarily to the higher personnel costs of multiple centers. The cost advantage of a single center is accentuated if equipment-investment costs are considered.