Appendix 3 - Nonresponse Follow-up Study 2019-0912

Marine Recreational Information Program
Fishing Effort Survey
Nonresponse Follow-up Study
9/12/2019

The MRIP Fishing Effort Survey (FES) was implemented in Massachusetts, New York, North
Carolina and Florida in October 2012 to test a revised data collection design for monitoring
marine recreational fishing effort. The survey, which collects information for two-month
reference waves, included a nonresponse follow-up study (NRFU) to assess nonresponse bias in
the FES.
Each wave, a sample of 320 FES nonrespondents was randomly selected and mailed a follow-up
questionnaire. Data collection for the study was initiated six weeks after the final contact for the
FES with the delivery of an advanced letter via regular first-class mail. Five days later, a survey
packet, including a cover letter, questionnaire, post-paid return envelope and a $5.00 cash
incentive was delivered via FedEx. The NRFU survey instrument was identical to the instrument
used for the FES.
Table 1 provides the initial sample sizes, number of completed interviews and response rates for
the NRFU. Overall, 839 nonresponse surveys were completed, resulting in an unweighted
response rate (AAPOR RR1) of 37.5%.
Table 1. Sample sizes, completed interviews and response rates.
State
Florida
Massachussets
New York
North Carolina
All

Sample
Size
598
533
510
599
2240

Completed
Interviews
203
216
172
248
839

Response
Rate (%)
34
40.5
33.7
41.4
37.5

We assessed nonresponse bias by comparing estimated fishing prevalence (percent of households
that reported fishing during the wave) between the initial FES and NRFU samples. Differences
between FES and NRFU estimates would suggest that FES and NRFU samples are different with
respect to recreational fishing activity, resulting in biased FES estimates.
Table 2 shows that differences in estimated fishing prevalence between initial samples and
NRFU samples are neither significant nor systematic, demonstrating that FES respondents and
nonrespondents are not significantly different with respect to saltwater fishing activity. This
suggests that nonresponse is not a significant source of bias in the FES.

Table 2. Estimated fishing prevalence for the FES sample and nonresponse follow-up sample.

State
Florida
Massachussets
New York
North Carolina
All

FES Sample
%
n
21.5
11,767
11
11,094
8.6
8,479
11.4
13,570
13.9
49,910

Nonresponse
Sample
%
n
18.4
203
13.2
216
9.2
172
9.8
248
12.7
839

p-value
0.2846
0.3077
0.7795
0.4295
0.3173