{"id":1933,"date":"2024-04-09T00:00:15","date_gmt":"2024-04-09T00:00:15","guid":{"rendered":"https:\/\/contentguru.builtbytoast.uk\/?post_type=resource&p=1933"},"modified":"2026-02-19T12:19:20","modified_gmt":"2026-02-19T12:19:20","slug":"calculating-erlang-a","status":"publish","type":"resource","link":"https:\/\/www.contentguru.com\/en-gb\/resources\/blogs\/calculating-erlang-a\/","title":{"rendered":"Testing Customer Patience with the Erlang A Formula"},"content":{"rendered":"\n\n
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Blogs<\/div>\n

Testing Customer Patience with the Erlang A Formula<\/h1>\n
Published: April 9th 2024<\/div>\n <\/div>\n <\/div>\n\n \n <\/section>\n\n\n\n\n\n
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In our last blog,\u00a0we went into detail on Erlang C; the formula commonly used for calculating the number of agents needed to service a queue of a given size.<\/a>\u00a0Erlang C is at the heart of contact center service levels, but there\u2019s another formula that adds another level of depth to our analysis; the Erlang A formula.<\/p>\n

In short, Erlang A goes one step further than Erlang C, in that it adds additional depth to its portrait of the customer. It measures\u00a0customer patience<\/b>.<\/p>\n

How is this done, how does it interact with the original Erlang C calculation, and how can you integrate its insights into your contact center operations? Is the sequel, for once, better than the original? Read on to discover more.<\/p>\n

Before we continue, optimizing contact center performance depends on more than Erlang A. To go in-depth on contact center performance metrics,\u00a0download Content Guru\u2019s whitepaper:\u00a0Keeping Up With the KPIs: The Contact Center KPIs Key to Outstanding CX.<\/b><\/a><\/p>\n <\/div>\n <\/div>\n <\/div>\n<\/div>\n\n \n <\/section>\n\n\n\n\n\n

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What is Erlang A?<\/strong><\/h2>\n

Erlang A was developed thirty years after the original Erlang C, in 1946, by Swedish mathematician, Cony Palm. (In addition to Erlang A and C, there is also a secret sibling, Erlang B, though this is not relevant to the operation of modern contact centers.)<\/p>\n

Erlang C, whilst essential, missed out on a critical aspect of customer behavior; customer patience. It assumed that, once a customer queued up, they would remain in the queue until their call was answered. This is obviously not true for the real world. Customers run out of patience and\u00a0abandon<\/b>\u00a0their calls. (A<\/i>\u00a0stands for\u00a0abandons<\/i>. See? Now we\u2019re starting to appreciate the mystery of the thing.)<\/p>\n

Erlang A offers a number of crucial benefits that Erlang C fails to account for:<\/p>\n