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Social Media Bandwagon

© Matt Hamm


Social Media Index (SM-i)

Academics have created indices to compare both scholars (h-index) and journals (Impact Factor) within a given field. The websites that contribute to the creation of Free Open-Access Medical Education (FOAM) do not have a comparable parameter. This makes assessing the impact of each website challenging for both content producers and their supervisors. Additionally, consumers of the information are unable to distinguish between reputable and unproven websites.

The Social Media Index (SM-i) was developed to fill these gaps. It is a comparative index derived from five easily obtainable indicators including: Google PageRank, Alexa Rank, Twitter Followers (of the most prominent regular contributor), Facebook Likes (site-specific) and Google+ Followers (site-specific). The details of the calculation of the SM-i are explained below. 

This is the fourth iteration of the scale. The first two versions were hosted at BoringEM and the third, posted just last week, was replaced with a revised and more methodologically sound index that is described below. It uses data gathered on the evening of November 15th, 2013. Please provide feedback/comments by posting on the blog post corresponding to the latest update, e-mailing Brent Thoma or tweeting @Brent_Thoma.

RankWebsiteAlexa (/1000)PageRankTwitterFacebookGoogle+SM-i
2Life in the Fast Lane87513765656611317.39
3Academic Life in EM*12354530145505256.68
4Dr. Smith's ECG Blog224542206978904.48
5The NNT1552633037304.08
7Ultrasound Podcast1753427759046293.88
8The Poison Review11565224685503.78
11Intensive Care Network1121332765734593.56
13Emergency Medicine Ireland16414264601963.44
14Emergency ECG Video of the Week132335227003.39
15EM Lit of Note1104425190243.39
16St. Emlyn's5773261902543.37
18The Trauma Professional's Blog246641841003.06
21Broome Docs118831900002.94
23SMART EM23184075702.91
20The Short Coat382241317002.81
22Pediatric EM Morsels3782718002.63
24The Chart Review16833335002.62
25EM Res Podcast7704410967802.44
26EM Basic32012248222702.42
27Adventure Medicine33703238002.38
29Sketchy Medicine35543294002.36
30Underneath EM26832106001202.33
31MedEd Life126404530212.30
32Tox Talk8602452712502.30
33Skeptic's Guide to EM5660382945902.29
36EM Lyceum279325555002.17
37ER Jedi5135311002.16
38EM PEM6297354512202.15
41The Sono Cave378126780582.10
42Don't Forget the Bubbles3050970129222.06
43PEM ED7906378816802.06
44REBEL EM1440012651842151.98
45Rural Flying Doc*280411218001.92
48A Life at Risk526928596241.85
46MD Aware1064022966001.83
50Manu et Corde*30771557001.79
49EM Nerd20960148001.53
51Renal Medicine962521798801.50
53Expensive Care112702478001.43
55Flipped EM Classroom63230246001.09
56KI Docs96380959000.94
57The Rolobot Rambles1250601941000.90
58The RAGE Podcast05918000.86
59ECG of the Week247302373000.72
60EM J Club17165039659340.45
Last update: Nov 14, 2013. 
*The PageRank score of these sites’ redirect addresses (ie / were used.


The fourth version of the SM-I marks its first change in methodology. Previously, an ordinal analysis was conducted as part of the rankings. Because that resulted in the loss of a significant amount of data, a new process was developed. Additionally, the raw values for each parameter are included in the chart to increase transparency. One of the benefits of this approach is that non-indexed sites can calculate their own score using the formula and the max values listed below.

In words, each website’s score is divided by the highest score for that indicator and multiplied by two. The scores for all indicators are then added together to give the SM-I for a given website. If a website had the best value for all five indicators they would have a SM-i of 10. For the Alexa score, the calculation is more complicated because of the huge values and inversion (the lowest score is the highest ranked).

Most simply, you can calculate the SM-i for any FOAM website using the simplified formula for this update: 

SM-i = (PR/3) + (Twit/6882.5) + (FB/7275) + (G+/1378) + (157.26 – (SQRT[Alexa*])/73.97))

*Note that the Alexa Rank used in the formula is Alexa/1000 just like it is presented in the table.

The simplified formula is the same as the one below but with all of the known values entered. The full SM-i formula (with legend) is:

SM-i = (2 x (PRw/PRm)) + (2 x (Tw/Tm)) + (2 x (FBw/FBm)) + (2 x (Gw/Gm)) + (2 x (SQRT[Amax] – SQRT[Aw])/(SQRT[Amax] – SQRT[Amin]))

 Website Value SymbolMax Value SymbolMax ValueMin Value SymbolMin Value
Alexa (/1000)AwAmax24730Amin87

Brent Thoma, MD MA
ALiEM Associate Editor
Simulation Fellow at Massachusetts General Hospital/Harvard Medical School
Emergency Medicine Resident at the University of Saskatchewan
Editor/Author at
Brent Thoma, MD MA