AJIn May 2013, Angelina Jolie announced of her decision on receiving the preventative double mastectomy. The news has instantly gone viral due to her global popularity and her symbolism as the epitome of female beauty. The public, for the most part, praised her bravery of choosing her health over the “superficial standards of beauty”.(1) The weekly Methods Discussion Group meeting at the University of Alberta’s School of Public Health has touched on this topic promptly after the news.

During that 1-hr discussion session, many public health-related questions were raised including “How to properly interpret individual cancer risks that are calculated from population data?”,(2) “Is it unethical for Myriad Genetics to seek patents on BRCA1 and BRCA2 genes by merely discovering their natural existence?”,(3) and “Do celebrity news change the level of cancer prevention awareness in the general public?” Five months have gone by, I thought it would be worthwhile to do a quick search using Google Trends (4) to shed some light on the last question.

Google Trends

By entering a word or phrase, Google Trends shows how often such search-term is entered relative to the total search-volume across different regions of the world. The horizontal axis represents time while the vertical axis indicates how often a term is searched that is relative to the highest number of search over the period. The highest search point is always given a 100 percent, so for example, if the highest point represents a search volume of 2,000 hits, another point at 1 percent will represent (2,000*1%) = 20 hits. The default location is global but smaller regions (ie: country and province) can be specified. If we assume the relative search frequency represents the degree of public interest, we will have a time-series to monitor the specific public interests around Angelina’s news announcement. Putting it in epidemiology terms, it will be an observational time-series without a control group.

Working Assumptions

Many important assumptions should be kept in mind when drawing generalizable conclusions based on open-access internet data. 1) It is assumed that Google accurately recorded and presented the numbers, 2) The search volume directly or indirectly measure the underlying public interest on a subject matter, and 3) The sample population was generalizable to the target population. For assumption #1, I think we could rely on Google’s capability to accurately capture and present the numbers on the face value.

Assumption #2 was also fairly reasonable as people typing the terms “Angelina Jolie” or “mastectomy” in Google search during that time frame should genuinely want to know more about them, as supposed to be searching them for school projects or job duties that didn’t warrant an inherent interest. Although there are other search engines like Yahoo and Bing, their total search volumes are just too measly comparing to Google. More importantly, what constitutes “interest” is up for philosophical and semantic debates as interests can have different quality and quantity. Quantitatively, the magnitude of interest cannot be entirely captured by a single search term. Hence, a better way to show the level of interest is a comprehensive and hierarchical set of related search terms for a particular subject matter. And I will apply this approach on a small scale below for the concept of cancer prevention awareness through the inclusion of multiple terms – “cancer prevention”, “cancer signs”, “self-breast exam”, and “breast exam”.

For assumption #3, since Google only captures search volume from people who are computer literate and already have computer access, it will be a judgment call to consider whether or not the sample population effectively represents the target population (a.k.a. the entirety of the general public). Despite these assumptions, Google Trends serves as a very powerful, free and timely tool to assess general public interest.

Patterns from Google Trends

1Both the terms “Angelina Jolie” and “mastectomy” had a huge spike representing a sharp increase in public interest in May 2013 during and shortly after the announcement took place. There was very little interest in “mastectomy” in the decade prior to the news, and it was safe to say that the large increase in interest was solely due to the news. However, these spikes only suggested relative increase in public interest, further comparisons should be made to reflect the underlying absolute magnitude of these interests.
2By comparing to the search term “news”, the search volumes of “Angelina Jolie” and “mastectomy” seemed very low. But “news” is probably one of the most commonly-searched terms worldwide, and the kind of interest for people searching for “news” was vastly different than the kind of interest for people searching for “Angelina Jolie” or “mastectomy”. Thus, a fairer comparison is needed.
3The term “Obama” is a better comparator as he represents one of the most important and popular politicians in the global arena within recent years. And many aspects between famous politicians and celebrities overlap. The fact that the search volume of “Angelina Jolie” surpassed “Obama” and “mastectomy” being about one-third of “Obama” search volume further confirmed the large extent of public interest after the news announcement.
4And the interest was not restricted to North America but indeed a global phenomenon (note: the low relative volume in China was due to the language difference as the citizens in China would primarily be searching for “安吉丽娜•朱莉” rather than “Angelina Jolie”).
5The added term “breast cancer” showed interesting cyclical patterns with spikes corresponding to Cancer Awareness Months.(5) Very surprisingly, there was no sharp spike for “breast cancer” during May 2013. This suggested that people interested in “Angelina Jolie” and/or “mastectomy” didn’t necessarily have the same heightened interest to know more about the very type of cancer Angelina was trying to prevent.



To dig deeper, I added search terms that were indicative of public’s interest in preventing breast cancer, including “cancer prevention”, “cancer signs”, “breast self-exam” and “breast exam”. Yet again, none of these terms had any notable increase during or following Angelina’s news.

To more confidently draw causal inferences between public news and public interest will require a fully methodologically sound study. Although Google Trends’ results were by no means comparable to a full, well-planned study, it provides free and accessible information for quick investigation. Hereby applying Google Trends to look at Angelina’s brave and admirable act as a case study, it seemed that the general public had an instant and explosive interest in learning more about Angelina Jolie following her news. This primarily motivated them to know more about the mastectomy procedure which was beneficial on a massive scale. However, the level of interest quickly subsided back to the baseline level prior to the news. In terms of cancer awareness and prevention, the above trends suggested the majority of the public did not go beyond the superficial search to delve deeper into the internet resources for information on breast cancer prevention. Merely hearing celebrity personal stories was insufficient to ignite and sustain public interest in cancer prevention. Nevertheless, public health researchers and professionals might want to look into opportunities in the news media to identify effective and complementary strategies to raise cancer prevention awareness in the general public.

Picture Courtesy


  1. Thebarge S. Angelina Jolie’s breasts and the bravery of letting go. 2013 [cited 2013 03-09-2013]; Available from: http://storylineblog.com/2013/08/23/angelina-jolies-breasts-and-the-bravery-of-letting-go/.
  2. Campbell D. Angelina Jolie’s double mastectomy – key questions answered. The Guardian; 2013 [cited 2013 27-08-2013]; Available from:http://www.theguardian.com/society/2013/may/14/angelina-jolie-double-mastectomy-qanda.
  3. Nelson R. Myriad BRCA patents nixed: what happens next. Medscape; 2013 [cited 2013 27-08-2013]; Available from: http://www.medscape.com/viewarticle/806689.
  4. Google Trends. 2013 [cited 2013 29-08-2013]; Available from: http://www.google.com/trends/.
  5. Choose Hope. Calendar of Cancer Awareness Months. 2013 [cited 2013 03-10-2013]; Available from: http://www.choosehope.com/calendar-of-cancer-awareness-months.

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