Measuring parental barriers to childhood immunizations: the development and validation of the searching for hardships and obstacles to shots (SHOTS) instrument.

There is a plethora of literature on barriers to immunizations; however, these studies lack standardization of measurement. The aim of this study was to develop and establish an initial psychometric evaluation of an instrument to measure parental barriers to childhood immunizations. This was a cross-sectional study design. Data analysis included descriptive statistics, reliability estimates, item analysis, and factor analysis. Six hundred and fifty-five participants completed the survey. The Searching for Hardships and Obstacles to Shots instrument was developed with 60 items and reduced to 23 items thorough multiple statistical computations; the best factor model was a three-factor solution (Access to Shots, Concerns About Shots, and Importance of Shots) with a total variance explained of 59.4%. The Cronbach's alpha reliability estimates ranged from .86 to .93, and temporal stability was adequate ( r = .85). This study supports exceptional initial psychometric properties of an instrument to measure parental barriers to childhood immunizations. Keywords: immunization barriers; pediatrics; questionnaire Recent media attention to the issues of safety surrounding childhood immunizations fuels the continuing need to break down the barriers to immunizations. Prevention of disease through immunizations is one of the best public health success stories. Despite the fact that many children receive immunizations, there are still some who lag behind. From national surveys, one can identify associations between low immunization rates and demographic variables, such as age, gender, or marital status; however, the reason why these differences in rates occur cannot be determined. There is a plethora of literature on barriers to immunizations in both children and adults; however, these studies lack standardization of measurement (Parve, 2004; Taylor et al., 2002; Thomas, Kohli, & King, 2004; Zimmerman et al., 2001). Most researchers develop questionnaires based on the literature and panels of "experts" without attending to the psychometric properties of the instrument. Furthermore, many studies attempting to identify barriers to immunizations do not include variables known to be barriers in their instruments or measurements (Mills et al., 2005). Therefore, there is a need to create a reliable and valid instrument to identify parental barriers to childhood immunizations. The overall aim of this study was to develop and assess psychometric properties of an instrument designed to measure parental barriers to childhood immunizations. BACKGROUND AND CONCEPTUAL FRAMEWORK Background The reduction of health disparities among all people in the United States is a national health priority. This goal is one of the top agenda items for leading public health initiatives such as Healthy People 2010 and health agencies like the Centers for Disease Control, the Department of Health and Human Services, and the National Institutes of Health (U.S. Department of Health and Human Services, 2002). Embedded in these initiatives is the reduction of disparities in immunization rates that occur by race/ethnicity, income, geographic areas, and other factors. Although this goal has been a high priority in the United States, disparities in immunization coverage rates still exist among children and adolescents of different racial, ethnic, and socioeconomic groups (Niederhauser & Stark, 2005). It is difficult to identify a causal relationship between ethnicity, racial groups, or socioeconomic status for the differences in immunization coverage; however, beliefs about the importance and necessity for vaccination are often affected by parental values and culture (Grabenstein, 2001). Knowledge about factors associated with suboptimal immunization rates is abundant in the literature (American Academy of Pediatrics, 2003; Luman, McCauley, Shefer, & Chu, 2003; Luman et al., 2001; Parve, 2004). In addition, it has been well documented that different parental barriers exist with various ethnic groups and in families with lower socioeconomic status (Brenner, Simons-Morton, Bhaskar, Das, & Clemens, 2001; Busch, Easa, Grandinetti, Mor, & Harrigan, 2003; Flynn-Saldana, Kirsch, & Lister, 2003; Grabenstein, 2001; Herrera, Zhao, & Klevens, 2001; Simpson, Suarez, & Smith, 1997; Strine et al. …