Awarded 2018 Best E-Newsletter by the National Association of Government Communicators
Environmental Factor

Environmental Factor

Your Online Source for NIEHS News

January 2019

Top stories of 2018 dominated by cell phone studies

In a milestone year for the Environmental Factor, a look at the top 20 stories reveals coverage of draft and final cell phone studies dominated reader interest.

Kelly Lenox editor in chief of the Environmental Factor Lenox has served as editor in chief of the Environmental Factor for the past 5 years. (Photo courtesy of Steve McCaw)

The past year was a milestone year for the Environmental Factor. The NIEHS flagship newsletter was named the best e-newsletter in the country by the National Association of Government Communicators (NAGC). This was the second award in as many years from NAGC, which named a piece by Science Editor Robin Arnette, Ph.D., as the best web article award in 2017.

Environmental Factor staff took a look back at the top 20 stories in 2018 and found some interesting patterns.

  • Coverage of the National Toxicology Program’s (NTP) draft and final studies on cell phone radio frequency radiation accounted for 29 percent of pageviews to monthly issues in 2018.
  • Subjects of the top 20 stories were evenly divided among the institute’s three divisions and ONE NIEHS stories, which are the topics that crossed divisional lines.
A bar graph showing the top 20 stories of 2018 and how many pageviews each story had.The top 3 subjects were "NTP cell phone studies peer review" with approximately 9500 pagesviews, "NTP Cell phone studies final reports" with just over 7000 pageviews, and "DDT exposure and autism" with around 6800 pageviews. Stories on the NTP cell phone radiofrequency radiation studies dominated readers’ interest in 2018.


For a monthly online publication, compiling lists like the top 20 is tricky. Our stories remain freely available and continue to attract readers in the months and years following their publication, through social media networks and internet searches.

For example, the 18th ranked story, published in August, described visits by NIEHS and NTP Director Linda Birnbaum, Ph.D., and others to several cities in California’s San Joaquin Valley, to learn about local environmental health concerns. As groups involved in environmental health around the valley shared the story among their networks — through social media, newsletters, and other means — readers continued to come to that page over the next four months of the year.

Through these means, Environmental Factor stories have what statisticians call a long tail. Most readers visit the website in the first couple of days after a new issue is published, and then readership continues at a much reduced level. Thus, one might expect a greatest hits list to be weighted toward stories published early in the year.

That is somewhat the case, as shown below. We would not be surprised if the November story on the final NTP cell phone radio frequency radiation studies appears on the 2019 top stories list.

A bar graph depicting which months had the most top stories. April came in first with 5 top stories Even though stories published early in the year have more time to attract readers, several from late summer and autumn appeared in the top 20 as well.

Another way to consider the pageviews across the year is presented in the chart below, called a TreeMap, which shows both the big picture as well as how the months relate to each other. The ranking of months places the most pageviews top left, and the least at the bottom right. Months without a top 20 story are not shown. Color shading from dark to light indicates beginning of the year to end.

A TreeMap graphic showing the page titles of the top stories for each month. The top 3 stories were "NTP cell phone studies — experts recommend elevated conclusions" from the April issue, "High exposure to radio frequency radiation associated with cancer in male rats" from the November issue, and "New insights on pesticide exposure and autism" from the September issue. A TreeMap displays the top 20 stories in boxes sized to represent the story and issue rankings, and shaded to indicate early (darker) compared with late (lighter) in the year.

Featured stories rank highly

We wondered which sections of the newsletter carry the most popular stories. The pie chart below shows that that stories featured prominently at the top of the newsletter account for half of the top-ranked articles. Unfortunately, data are not available to tell us whether they are top stories because they are featured, or whether our selection process is good at determining public interest.

A pie graph depicting the number of top stories by section. Papers Published has 3, Awards Recognition as 3, Science Highlights has 4, and Feature stories has 10 Half of the top 20 were published as feature stories. The three top sections were evenly represented among the other 10 stories.

Three of the five sections are equally represented. Science Highlights, Awards and Recognition, and Papers Published generally carry more stories in an issue than the two that are not represented — Community Impact and Beyond the Bench.

Subjects represent full range of NIEHS programs

Popular stories reflect the work of each of the institute’s three divisions, listed below, as well as activities and research that cross divisional lines, which we call ONE NIEHS. See, for example, the story on a new North Carolina group focused on endocrine disruptor research.

  • The Division of Intramural Research (DIR) or in-house researchers.
  • The Division of Extramural Research (DERT), which is the grants program.
  • The Division of the National Toxicology Program (DNTP).

And yet, our efforts are only part of what attracts readers. Topics in the news also play a role, including cutting-edge science, like the microbiome and autoimmunity; discoveries of mechanisms involved in challenging diseases like ataxia and Parkinson’s; and cases of newly-discovered drinking water contamination, for instance, with per- and polyfluoroalkyl substances (PFAS).

A chart showing how many top stories each division had along with the page titles. One NIEHS division had 6 top stories. DNTP had 4 top stories. DIR had 5 top stories. DERT had 5 top stories. Looking at story topics by NIEHS division, where ONE NIEHS refers to those that involved cross-divisional content, the categories are evenly divided.

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