OJPHI: Vol. 5
Journal Information
Journal ID (publisher-id): OJPHI
ISSN: 1947-2579
Publisher: University of Illinois at Chicago Library
Article Information
©2013 the author(s)
open-access: This is an Open Access article. Authors own copyright of their articles appearing in the Online Journal of Public Health Informatics. Readers may copy articles without permission of the copyright owner(s), as long as the author and OJPHI are acknowledged in the copy and the copy is used for educational, not-for-profit purposes.
Electronic publication date: Day: 4 Month: 4 Year: 2013
collection publication date: Year: 2013
Volume: 5E-location ID: e66
Publisher Id: ojphi-05-66

Content Analysis of Tobacco-related Twitter Posts
Mark Myslín*
Shu-Hong Zhu
Michael Conway
UC San Diego, San Diego, CA, USA
*Mark Myslín, E-mail: mmyslin@gmail.com

Abstract
Objective

We present results of a content analysis of tobacco-related Twitter posts (tweets), focusing on tweets referencing e-cigarettes and hookah.

Introduction

Vast amounts of free, real-time, localizable Twitter data offer new possibilities for public health workers to identify trends and attitudes that more traditional surveillance methods may not capture, particularly in emerging areas of public health concern where reliable statistical evidence is not readily accessible. Existing applications include tracking public informedness during disease outbreaks [1].

Twitter-based surveillance is particularly suited to new challenges in tobacco control. Hookah and e-cigarettes have surged in popularity, yet regulation and public information remain sparse, despite controversial health effects [2,3]. Ubiquitous online marketing of these products and their popularity among new and younger users make Twitter a key resource for tobacco surveillance.

Methods

We collected 7,300 tobacco-related Twitter posts at 15-day intervals from December 2011 to July 2012, using ten general keywords such as cig* and hookah. Each tweet was manually classified using a tri-axial scheme, capturing genre (firsthand experience, joke, news, …), theme (underage usage, health, social image, …), and sentiment (positive, negative, neutral). Machine-learning classifiers were trained to detect tobacco-related vs. irrelevant tweets as well as each of the above categories, using Naïve Bayes, k-Nearest Neighbors, and Support Vector Machine algorithms. Finally, phi correlation coefficients were computed between each of the categories to discover emergent patterns.

Results

The most prevalent genre of tweets was personal experience, followed by categories such as opinion, marketing, and news. The most common themes were hookah, cessation, and social image, and sentiment toward tobacco was more positive (26%) than negative (20%). The most highly correlated categories were social image–underage, marketing–e-cigs, and personal experience–positive sentiment. E-cigarettes were also correlated with positive sentiment and new users (even excluding marketing posts), while hookah was highly correlated with positive sentiment, pleasure, and social relationships. Further, tweets matching the term “hookah” reflected the most positive sentiment, and “tobacco” the most negative (Figure 1). Finally, negative sentiment correlated most highly with social image, disgust, and non-experiential categories such as opinion and information.

The best machine classification performance for tobacco vs. nontobacco tweets was achieved by an SVM classifier with 82% accuracy (baseline 57%). Individual categories showed similar improvements over baseline.

Conclusions

Several novel findings speak to the unique insights of Twitter surveillance. Sentiment toward tobacco among Twitter users is more positive than negative, affirming Twitter’s value in understanding positive sentiment. Negative sentiment is equally useful: for example, observed high correlations between negative sentiment and social image, but not health, may usefully inform outreach strategies. Twitter surveillance further reveals opportunities for education: positive sentiment toward the term “hookah” but negative sentiment toward “tobacco” suggests a disconnect in users’ perceptions of hookah’s health effects. Finally, machine classification of tobacco-related posts shows a promising edge over strictly keyword-based approaches, allowing for automated tobacco surveillance applications.


References
[1]. Chew C, Eysenbach G. Pandemics in the age of twitter: Content analysis of tweets during the 2009 H1N1 outbreakPLoS One 2010;5(11):e14118.
[2]. Ayers JW, Ribisl KM, Brownstein JS. Tracking the rise in popularity of electronic nicotine delivery systems (Electronic cigarettes) using search query surveillanceAm J Prev Med 2011;40(4):448–453.
[3]. Grekin ER, Ayna D. Waterpipe smoking among college students in the United States: A review of the literatureJ Am Coll Health 2012;60(3):244–249.

Figure
ojphi-05-66f1.tif
[Figure ID: f1-ojphi-05-66]
Figure: 

Sentiment in "hookah" tweets is disproportionately more positive than in "cig" and especially "tobacoo" tweets



Article Categories:
  • ISDS 2012 Conference Abstracts

Keywords: social media, surveillance, Twitter, tobacco, NLP.




Online Journal of Public Health Informatics * ISSN 1947-2579 * http://ojphi.org