Summary of findings and limitations
We designed a radon education app as a communication tool to increase radon awareness. Our most important findings were the positive effects of radon app on knowledge, attitudes toward testing, and coping appraisal. We found that the concepts of self-efficacy and response efficacy were significant predictors of ordering a radon test kit.
The app was clearly effective in increasing radon knowledge. Participants were able to correctly identify the threat (i.e., radon gas), the consequence of the threat (i.e., lung cancer), and how to prevent it (i.e., via testing the house and utilizing a radon mitigation system). These are the core elements of radon risk communication. The positive effects of app on improved knowledge suggest that delivering content in short, simple terms via a mobile app is an effective way to communicate radon-related information. The app is a very different style of content delivery than the explanations typically used in pamphlets and brochures [
11,
12] or in telephone interviews [
9,
10]. With several notable exceptions [
8,
12,
23] – e.g., an increase in radon test kit purchases reported among individuals exposed to digital signs in physicians’ waiting rooms [
8] – few intervention studies have reported that the intervention improved individuals’ knowledge, attitudes, perceptions, or behaviors.
The levels of radon knowledge and attitudes toward radon testing increased in the post-exposure test, a finding consistent with the results of several studies regarding radon knowledge [
12]. Notably, improved knowledge and attitudes by themselves were not significant predictors of ordering the test kit. Many studies have assumed that the critical problem underlying low radon testing and home remediation rates is individuals’ lack of understanding about radon. On this view, the primary objective of radon intervention strategies has been information delivery [
24]. This assumption is based on the deficit model [
25] whereby individuals fail to perform positive behaviors due to the lack of knowledge or understanding. Conversely, our findings indicate that an increase in individuals’ knowledge does not reliably predict positive behavioral changes.
We found that coping appraisals – response efficacy and self-efficacy – were the most significant predictors of ordering a test kit, which is consistent with previous studies [
23]. Interestingly, threat appraisals – perceived severity and perceived susceptibility – did not increase the likelihood of ordering a test kit. This could be because participants already understood the severity of the threat even before using the app in T1. Despite a high level of perceived severity, perceived susceptibility was consistently low both in T1 and T2. This is consistent with the findings of many studies of radon knowledge, which demonstrate that respondents display “optimistic bias”, i.e., the view that radon is more of a danger to
others than to themselves [
7]. Additionally, young individuals in particular often do not consider themselves to be at risk of cancer or death [
26].
Our study has several limitations. First, use of a student sample limits the generalizability of our findings. Thus, these findings should be replicated with a more generalizable sample. Because our primary focus was testing the app’s feasibility, we did not perform power analyses a priori in order to determine the optimum sample size. Additionally, the ultimate target audience of a radon-education app is homeowners/homebuyers. Compared to undergraduates, homeowners tend to be older, e.g., the median age of first time home-buyers in the US is 33 [
27] and older individuals may have lower smartphone literacy [
28]. Secondly, our pretest-posttest design did not include an unexposed group. Finally, some idealized conditions applied, i.e., the app was installed on participants’ phones. In the “real world,” there may be disincentives to install such software, which may be regarded as undesirable (i.e., “bloatware”).
Conversely, our study has several strengths. To our knowledge, this is the first study to use a smartphone app to address radon knowledge and beliefs. The app significantly improved radon knowledge and coping appraisals. Notably, our use of coded test kits allowed us to measure actual ordering and testing behaviors as well as view the lab results for completed radon tests. Nearly a quarter of participants (24%) used the app to order the free test kit. However, of the participants who ordered the free test kit, only two ultimately returned the kit to the laboratory, resulting in a test process completion rate of 9%. This relatively low rate is consistent with the interpretation of Doyleand colleagues [
13] who emphasized the many opportunities for “failure” of educational campaigns to produce home mitigation; e.g., individuals first must learn about radon, obtain a test kit, use the test kit, return the kit, interpret the test results, and, if warranted, ultimately remediate their home, a process which itself contains numerous opportunities for lack of follow through. Although our results did not involve individuals who remediated their homes, our findings identified the step, “using the test kit” as an important opportunity for failure in the overall goal of home remediation. This vulnerability is faced by many public health interventions, e.g., “at home” disease screening tests which often are not returned to the laboratory after they are obtained [
29]. However, a smartphone app is ideally suited to the use of methods to increase test kit use, such as the addition of in-app reminders to individuals who have received the test kits but not yet returned them. The use of such reminders would be a logical and feasible next step to improve the test process completion rate.