General information

The LA County 2015/05 List Sample sample cohort is characterized by the following:

VendorLA County
Sample descriptionZipcodes drawn of LA County residents
Date drawnNot applicable
Date of first mailingApril 14, 2015
Batch size1990

Recruitment rates

All the recruitment rates below conform to AAPOR specifications. Please note that the Initial Response Rate reported in table 1 are based on AAPOR RR1. More information about the AAPOR response rates can be found at the Aapor web site.

To download the below information as an AAPOR excel sheet, please just click here.

Mailout and phone follow up of initial survey

The initial mail survey is a standard paper and pencil mail survey. Hence, the response rate of this is computed like any mail survey.

Total sample1,990
Eligible refusals and noncontacts (R)
Refused to participate0
Incomplete interviews0
Refusals and noncontacts with unknown eligibility (U)
Nothing returned1,215
Undeliverable by mail226
Unreachable by phone0
Responses (I)549
Initial Response Rate (I/(I + R + U))31.1%

Consent to participate

The initial mail survey asks respondents whether they would be interested in participating in the Understanding America Study. Everyone who answers affirmatively and who receives a login code is considered to have provided consent. The recruitment rate is then calculated as the number of people who receive a login code divided by the total number of eligible responses to the mail survey.

Total sample549
Eligible refusals and noncontacts (R)
Refused to participate51
Refusals and noncontacts with unknown eligibility (U)0
Responses (I)498
Recruitment Rate (I/(I + R + U))90.7%

Initial participation

The profile rate (PROR) is the fraction of the individuals who consented who completed My Household and thus became a panel member.

Total sample498
Eligible refusals and noncontacts (R)
Logged on to survey, did not complete any item-2
Partially completed the My Household survey8
Did not log on238
Responses (I)254
Profile Rate (I/(I + R))51%

Overall recruitment rate

The overall recruitment rate (ORR) is the product of the response rates computed above (initial response rate, recruitment rate, and profile rate):

ORR = IRR * RECR * PROR = 0.311 * 0.907 * 0.51 = 14.4%

Active panel

As in any panel, we monitor attrition. Because individuals often simply stop responding without actively withdrawing from the panel and without us being able to contact them, we adopt the criterion that an individual is considered to be an active panel member if they participated in any survey in the last year (counting back from today, that is, October 22, 2019). A panel member who is not an active panel member but has not been removed yet from the panel is an inactive panel member.

Total sample254
Eligible refusals and noncontacts (R)
Voluntary drop-out0
Temporarily unavailable0
Individuals removed for miscellaneous reasons3
Refusals and noncontacts with unknown eligibility (U)
Inactive panel member109
Ineligible for another reason0
Responses (I)142
Retention Rate (I/(I + R + U)55.9%

Cumulative response rate

The cumulative response rate (CUMRR) up to and including retention is the product of the response rates computed above (initial response rate, recruitment rate, profile rate, and retention rate):

CUMRR = IRR * RECR * PROR * RETR = 0.311 * 0.907 * 0.51 * 0.559 = 8%