As more researchers use online panels for studies, the need for standardized rates to evaluate these studies becomes paramount. There are currently many different ways and conflicting terminology used to compute various metrics for online panels. This paper discusses the sparse literature on how to compute response, refusal, and other rates and proposes a set of formulas and a standardized terminology that can be used to calculate and interpret these metrics for online panel studies. A description of and distinction between probability-based and volunteer opt-in panels is made since not all metrics apply to both types. A review of the existing discussion and recommendations, mostly from international organizations, is presented for background and context. In order to propose response and other metrics, the different stages involved in building an online panel are delineated. Metrics associated with these stages contribute to cumulative response rate formulas that can be used to evaluate studies using online probability-based panels. (Only completion rates can be calculated with opt-in panels.) We conclude with a discussion of the meaning of the different metrics proposed and what we think should be reported for which type of panel.

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The Advisory Committee on Immunization Practices recommends annual influenza vaccination for all health care personnel to reduce influenza-related morbidity and mortality among both health care personnel and their patients (1-4). To estimate influenza vaccination coverage among U.S. health care personnel for the 2015-16 influenza season, CDC conducted an opt-in Internet panel survey of 2,258 health care personnel during March 28-April 14, 2016. Overall, 79.0% of survey participants reported receiving an influenza vaccination during the 2015-16 season, similar to the 77.3% coverage reported for the 2014-15 season (5). Coverage in long-term care settings increased by 5.3 percentage points compared with the previous season. Vaccination coverage continued to be higher among health care personnel working in hospitals (91.2%) and lower among health care personnel working in ambulatory (79.8%) and long-term care settings (69.2%). Coverage continued to be highest among physicians (95.6%) and lowest among assistants and aides (64.1%), and highest overall among health care personnel who were required by their employer to be vaccinated (96.5%). Among health care personnel working in settings where vaccination was neither required, promoted, nor offered onsite, vaccination coverage continued to be low (44.9%). An increased percentage of health care personnel reporting a vaccination requirement or onsite vaccination availability compared with earlier influenza seasons might have contributed to the overall increase in vaccination coverage during the past 6 influenza seasons.

The cultural and linguistic diversity of the U.S. population presents challenges to the design and implementation of population-based surveys that serve to inform public policies. Information derived from such surveys may be less than representative if groups with limited or no English language skills are not included. The California Health Interview Survey (CHIS), first administered in 2001, is a population-based health survey of more than 55,000 California households. This article describes the process that the designers of CHIS 2001 underwent in culturally adapting the survey and translating it into an unprecedented number of languages: Spanish, Chinese, Vietnamese, Korean, and Khmer. The multiethnic and multilingual CHIS 2001 illustrates the importance of cultural and linguistic adaptation in raising the quality of population-based surveys, especially when the populations they intend to represent are as diverse as California's.

Pregnant women and infants are at increased risk for influenza-related complications and hospitalization. Influenza vaccination can reduce the risk for influenza-related illness among pregnant women and their infants. Since 2004, the Advisory Committee on Immunization Practices (ACIP) and the American College of Obstetricians and Gynecologists (ACOG) have recommended influenza vaccination for all women who are or will be pregnant during the influenza season, regardless of trimester of pregnancy. To assess influenza vaccination coverage among pregnant women during the 2014–15 influenza season, CDC analyzed data from an Internet panel survey conducted during March 31–April 6, 2015. Among 1,702 survey respondents who were pregnant at any time during October 2014–January 2015, 50.3% reported receiving influenza vaccination before or during pregnancy, similar to the reported coverage in the preceding season. Overall, 64.9% of respondents reported receiving a provider offer of influenza vaccination, 14.8% received a recommendation but no offer, and 20.3% received no recommendation. Vaccination coverage among these groups of women was 67.9%, 33.5%, and 8.5%, respectively. Reminder systems and standing orders that allow health care personnel other than the attending provider to assess vaccination status and administer vaccination, can help to ensure that influenza vaccination is recommended and offered to a pregnant woman at each provider visit to increase pregnant women’s vaccination coverage.