Dial time

Interviewer - Server > Architecture > Interview Service tier > Dialer Interface component > Call log analysis for the predictive dialing algorithms > Dial time

Dial time

Dial time is the time between the dialer sending the request to the phone network and the respondent's phone starting to ring; in other words, the time the phone network takes to route the call to the respondent. This time is not insignificant with a mean of around two or three seconds.

The dial time for Project B was generally longer, probably due to the larger geographical area in the USA where the survey was being conducted. The standard deviation is relatively high indicating some variation in the dial time. Most calls start ringing within about four seconds, but a small percentage of calls can take significantly longer, as is evident from the number of small bars in the charts below and the maximum dial times of 22 and 30 seconds that have been recorded.

	Base	Project A	Project B
Base	269724 100%	200962 100%	68762 100%
Minimum: DialTime	1	1	1
Maximum: DialTime	30	22	30
Mean: DialTime	2.3	2.1	3.0
Standard Deviation: DialTime	1.28	1.05	1.61
Lower quartile	1.5	1.4	2.0
Median	1.8	1.7	3.0
Upper quartile	3.0	2.7	3.5

Dial time: Project A

Dial time: Project B

A separate analysis of the Project A data was performed to examine how the dial time varied depending on the number that was being dialed. There is a considerable amount of variation:

▪Calls to 020 numbers (London) are around one second with little variation. This may be because the dialer was in London.

▪Calls to 01X numbers (the rest of the UK) take slightly longer (one to two seconds) and show more variation than calls to London numbers.

▪Calls to 077, 078, and 079 numbers (cell phones) take significantly longer (three to six seconds) and show even more variation

▪Calls to 084X and 087X numbers (non-geographical) show a lot of variation.

▪Calls to international numbers are strongly dependent on the country being dialed. For example, calls to France (0033) took two to three seconds to dial while calls to Germany (0049) took around six to eight seconds.