Date of Graduation


Document Type


Degree Name

Doctor of Philosophy in Community Health Promotion (PhD)

Degree Level



Health, Human Performance and Recreation


Philip Massey

Committee Member

Mance Buttram

Second Committee Member

Wen-Juo Lo

Third Committee Member

Alex Russell

Fourth Committee Member

Jennifer Manganello


framing;health communication;human papillomavirus;Instagram;social endorsement;social media


The use of social network sites (SNS) to deliver health interventions has been on the rise in recent years due to their popularity among the general population and functionalities that facilitate interactions with the content, or with other users of SNS. Despite that, scholars have noted challenges, including low engagement, associated with SNS-delivered interventions. This dissertation’s overall purpose is 1) to document the current state of measuring engagement within SNS-delivered health interventions, and 2) to empirically examine the interplay between message framing, social endorsement and engagement in a randomized experiment using Instagram. Results from the scoping review showed that a majority of studies continue to use micro-level engagement indicators to define engagement with a given intervention, and few studies examined engagement as a potential effect modifier of intervention effect, making it difficult to ascertain the type of engagement that matters the most in driving behavioral change. Results from our experimental study (n=528) that utilized Instagram to deliver a human papillomavirus (HPV) vaccine promotion information showed that micro-level engagement did not mediate the relationship between framed messages and vaccination intention; instead, the study suggests that the effect of the communication intervention was partially mediated through positive emotion evoked as a result of reading the intervention material. Additionally, the study suggests that heuristic cues displayed on SNS, such as number of likes, could confer social endorsement effect, such that individuals will be more likely to “like” and “share” the post when they see many people have also liked the post. However, no differences were observed in terms of credibility perception between participants who were exposed to a post with high number of likes vs low numbers of likes in the current study context. This dissertation’s findings contribute to gaps in our understanding of engagement in the context of SNS-delivered interventions. Future works that incorporate multiple dimensions of engagement or utilize multiple methods will further our understanding of engagement and improve ways in which we can best utilize SNS for health intervention purposes.

Available for download on Saturday, August 30, 2025

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