Section 411.310  General Characteristics of the Customer Survey

a)         The customer survey shall start no earlier than September 1 and be completed by the end of the calendar year.  

b)         The survey can be conducted either over the phone, by electronic mail, U.S. mail or online or any combination of the preceding.

c)         For residential and nonresidential customers selected in the sample, the method used must be consistent with the contact information provided by the customer. For example, if a customer does not provide an e-mail address, then that customer shall not be surveyed via e-mail, and therefore must be surveyed via telephone, online, or U.S. Mail.

d)         The survey questions shall be identical for all jurisdictional entities.

e)         The survey shall be conducted for residential and non-residential customers. For the residential population, the survey respondent shall be the person in the household who is most familiar with the household's electric service. For non-residential customers, the survey respondent shall be the person who is most familiar with electric service in the organization.

f)         For each jurisdictional entity, the sample size shall be adequate to ensure that answers are reflective of the population at a specified statistical level of confidence and confidence interval as follows:

1)         For residential customers, sample size shall be sufficient to achieve a 95% confidence level with a confidence interval of ± 4.0%. This confidence level and confidence interval equates to 600 respondents for utilities with 10,000 or more residential customers. The sample size for utilities with fewer than 10,000 residential customers would be adjusted by a finite population correction factor calculated as (N-n)/(N-1), where N = population size and n = originally required sample size.

2)         For non-residential customers, sample size shall be sufficient to achieve a 95% confidence level with a confidence interval of ± 4.9%.  This level of confidence and confidence interval equates to 400 respondents for utilities with 10,000 or more non-residential customers and accordingly fewer (i.e., (N-n)/(N-1)) for smaller jurisdictional entities.

g)         Before eliminating a customer and randomly selecting a replacement, the jurisdictional entities shall:

1)         make a minimum of five attempts to contact each randomly selected customer to request that the customer complete the survey;

2)         for telephone surveys, attempt to reach the randomly selected customer at different times of day;

3)         for telephone surveys, call the customer back at the specified time if the customer answers the telephone but asks to respond to the survey at a different time; and

4)         for telephone surveys, call back at a time the target respondent is expected at home or office if the telephone is answered by anyone but the target respondent.

(Source:  Amended at 46 Ill. Reg. 5653, effective March 22, 2022)