Editing Call centre (section)

==Evaluation==
===Mathematical theory===
{{see also|Erlang distribution}}
[[Queueing theory]] is a branch of mathematics in which models of service systems have been developed. A call centre can be seen as a queueing network and results from queueing theory such as the probability an arriving customer needs to wait before starting service useful for provisioning capacity.<ref>{{Cite journal |last1=Gans |first1=N. |last2=Koole |first2=G. |last3=Mandelbaum |first3=A. |doi=10.1287/msom.5.2.79.16071 |title=Telephone Call Centers: Tutorial, Review, and Research Prospects |journal=[[Manufacturing & Service Operations Management]] |volume=5 |issue=2 |pages=79–141 |year=2003 |url=http://ie.technion.ac.il/Labs/Serveng/files/CCReview.pdf |archive-url=https://web.archive.org/web/20151208113728/http://ie.technion.ac.il/Labs/Serveng/files/CCReview.pdf |archive-date=2015-12-08 |url-status=live }}</ref> ([[Erlang's C formula]] is such a result for an [[M/M/c queue]] and approximations exist for an [[M/G/k queue]].) Statistical analysis of call centre data has suggested arrivals are governed by an [[inhomogeneous Poisson process]] and jobs have a [[log-normal distribution|log-normal service time distribution]].<ref>{{Cite journal |last1=Brown |first1=L. |last2=Gans |first2=N. |last3=Mandelbaum |first3=A. |last4=Sakov |first4=A. |last5=Shen |first5=H. |last6=Zeltyn |first6=S. |last7=Zhao |first7=L. |doi=10.1198/016214504000001808 |title=Statistical Analysis of a Telephone Call Center |journal=[[Journal of the American Statistical Association]] |volume=100 |issue=469 |pages=36–50 |year=2005 |url=http://132.68.160.12/serveng/References/statanalysis.pdf |archive-url=https://web.archive.org/web/20151208162908/http://132.68.160.12/serveng/References/statanalysis.pdf |archive-date=2015-12-08 |url-status=live |s2cid=1639154 }}</ref> Simulation algorithms are increasingly being used to model call arrival, queueing and service levels.<ref>{{Cite news|url=https://portagecommunications.com/a-primer-on-two-call-center-staffing-methods/|title=A Primer On Two Call Center Staffing Methods for Call Center Workforce Management|newspaper=Portage Communications|language=en-US|access-date=2016-10-14}}</ref>

Call centre operations have been supported by mathematical models beyond queueing, with [[operations research]], which considers a wide range of [[Optimization (mathematics)|optimisation problems]] seeking to reduce waiting times while keeping server utilisation and therefore efficiency high.<ref>{{Cite journal |last1=Borst |first1=S. |last2=Mandelbaum |first2=A. |last3=Reiman |first3=M. I. |title=Dimensioning Large Call Centers |doi=10.1287/opre.1030.0081 |journal=Operations Research |volume=52 |issue=1 |pages=17–34 |year=2004 |jstor=30036558 |url=http://iew3.technion.ac.il/serveng/References/Dimensioning.pdf |archive-url=https://web.archive.org/web/20030705052951/http://iew3.technion.ac.il/serveng/References/dimensioning.pdf |archive-date=2003-07-05 |url-status=live }}</ref>