*The "Mean salary of librarians per hour is taken from Table 2-1 of the National Compensation Survey: Occupational Wages in the United States, July 2002, U.S. Department of Labor, Elaine L. Chao, Secretary, Bureau of Labor Statistics, Kathleen P. Utgoff, Commissioner. September 2003. Bulletin 2561.
Available at: http://www.bls.gov/ncs/ocs/sp/ncbl0552.pdf (accessed November 6, 2003). This value was then adjusted from 2002 Dollars to 2003 dollars using the Inflation Calculator available at: http://www.bls.gov/ (accessed November 6, 2003).
Link to Heavy Traffic Digital Reference Cost Model
Formulas used for calculations:
"Labor cost of meetings (assuming 1 hour meetings) per year" equals the "Number of committee/task force/work group meetings per year" times the "Average meeting attendance" times the "Mean salary of librarians per hour."
"Cost of software per year" equals the "Number of service points" times the "Cost of software per year per seat."
"Cost of software per minute of service" equals the "Cost of software per year" divided by the quantity, 49 (assumes a 49 week year with 3 weeks of suspended service) times 60 times the "Number of service hours per week," end quantity.
"Mean salary for librarians per minute" equals "Mean salary for librarians per hour" divided by 60.
"Estimated labor cost per reference transaction" equals the "Average length of the reference transaction in minutes" times the "Mean salary for librarians per minute."
"Estimated total compensation per reference transaction (with fringe benefits)" equals the "Estimated labor cost per reference transaction" plus the quantity, "Estimated labor cost per reference transaction" times 28.3 divided by 71.7, end quantity. Note that 28.3 divided by 71.7 is the ratio of benefits to wages and salaries. Both numbers were cited in Employer Costs for Employee Compensation Summary for June of 2003 available at: http://www.bls.gov/news.release/ecec.nr0.htm (accessed November 4, 2003).
"Estimated total labor compensation per month" equals the "Reference transactions per month" times the "Estimated total compensation per reference transaction (with fringe benefits)."
"Estimated total labor compensation per year" equals the "Estimated total labor compensation per month" times 12 months times 49 weeks divided by 52 weeks.
"Estimated total cost per year" equals the "Labor cost of meetings (assuming 1 hour meetings) per year" plus the "Cost of software per year" plus the "Estimated total labor compensation per year."