Table 1.

Dimensions of attitude strength that may inform measurement of risk perceptions

Dimension of attitude strength	Definition in attitude literature	Application to risk perception measurement	Hypotheses concerning risk perceptions
Certainty	“The subjective sense of conviction one has about one’s attitude, or the extent to which one is confident or sure of one’s attitude” (Tormala & Rucker, 2007)	Conviction about one’s personal risk for disease could be measured and treated as either a moderator of perceived risk or alternative to perceived risk items.	See Table 3
Accessibility	“The strength of the object-evaluation link” which is manifested as “the ease with which an attitude comes to mind” (Krosnick & Petty, 1995, p. 6)	Accessibility about perceived risk could be assessed by asking people how frequently they have thought about a particular disease or their likelihood of getting it (Windschitl, 2003), or by asking about “preoccupation with thoughts about risk” (Weinstein, 2003). The potential application of attitude accessibility to risk perception measurement has been previously identified (see Windschitl, 2003) but does not seem to have been extensively pursued.	Risk perceptions that are higher in accessibility should be more predictive of behavior.
Extremity	“The extent to which the attitude deviates from neutrality” (Krosnick & Petty, 1995, p. 6); in other words, the positivity or negativity of an attitude.	Extremity of risk perceptions could be determined by assessing the extent to which perceived risk deviates from the midpoint of the response scale. At their most extreme (e.g., 0% or 100%), risk perceptions should be held with substantial certainty. However, individuals who believe their risk to be intermediate may feel very confident that this is the case or they may pick an intermediate degree of risk because they are uncertain of their risk.	Risk perceptions that are more extreme may be more predictive of behavior, to the extent that extreme risk perceptions are also held with greater conviction. We expect that risk conviction should be more useful to measure than risk extremity.
Importance	“The degree of psychological significance people attach to an attitude” and a “manifestation of the degree of personal relevance of the attitude object” (Krosnick & Petty, 1995, p. 7).	A potentially related construct in the health domain is illness centrality, which has been measured as the extent to which people “define themselves in terms of their illness” (Helgeson & Novak, 2007, p. 260). This construct refers to people who have an illness. Future research on illness centrality may benefit from applying lessons learned from research on attitude importance.	Perceived risk may be more likely to predict behavior when a disease is more central to one’s sense of self, for example when people have a family history of disease. For individuals who do not yet have a disease, risk importance or illness centrality (adapted for individuals without disease) could be measured for multiple diseases, which might indicate whether risk perceptions are likely to predict health behaviors for a particular individual.