Hand holding a Social Media 3d Sphere

Social Media Index (SMi)

UPDATE (June 2023): This is now retired because Alexa Rank data is no longer available. The revised formula to rank open access blogs and podcasts is the Digital Impact Factor.

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, learners may find it difficult to distinguish between reputable and unproven websites.

The Social Media Index (SMi) was developed to address these problems. It is a comparative index derived from three easily obtainable indicators including:

Alexa Rank (of the website)
Twitter Followers (of the website or most prominent editor – whichever is higher)
Facebook Likes (of the website’s page)

For each website, these 3 indicators are normalized and added together to give a score ranging from 0 to 10. The details of the derivation and validation of the SMi are outlined in the Western Journal of Emergency Medicine¹ while a study investigating the SMi’s correlation with quality has recently been published in Annals of Emergency Medicine.²The 2021 SMi was calculated in the last week of December, 2020. It will be updated annually each December moving forward.

2021 Social Media Index (SMi) Rankings

The SMi ranking table demonstrates the annual rankings of each site since 2016.

Website	2016	2017	2018	2019	2020	2021
LITFL	1	1	1	1	1	1
EMCrit	2	2	2	2	2	2
ALiEM	3	3	3	3	3	3
Rebel EM	9	7	5	5	4	4
Emergency Medicine Cases	10	6	7	6	6	5
Dr. Smith's ECG Blog	6	5	6	4	9	6
EM Docs	20	9	8	7	5	7
First 10 EM	35	19	19	11	7	8
RCEM Learning	NR	NR	NR	NR	NR	9
Don't Forget the Bubbles	21	42	15	12	15	10
EMS 12 Lead	5	4	4	9	10	11
WikEM	NR	NR	NR	NR	NR	12
Core EM	NR	NR	NR	NR	NR	13
CanadiEM	16	11	10	8	8	14
The Skeptic's Guide to EM	23	17	16	14	11	15
St. Emlyn's Blog	15	10	11	15	13	16
Core Ultrasound	14	12	18	17	14	17
The Resus Room	NR	NR	NR	NR	NR	18
Ultrasound of the Week	26	22	23	24	19	19
FOAMcast	52	50	20	19	20	20
Intensive Care Network	12	8	13	10	17	21
Emergency Medicine Updates	18	18	14	16	18	22
EM Basic	22	15	17	18	22	23
EM Ottawa Blog	NR	137	96	47	39	24
Taming the SRU	29	23	35	22	24	25
POCUS 101	NR	NR	NR	NR	NR	26
Journal Feed	NR	NR	NR	NR	NR	27
FemInEM	NR	NR	21	13	12	28
EM Lit of Note	17	13	29	25	21	29
The Gurney Room	NR	NR	NR	NR	NR	30
Resus	30	26	34	20	29	31
Resus ME	28	21	25	26	23	32
TotalEM	NR	NR	NR	57	25	33
Broome Docs	59	54	60	41	45	34
Pharmacy Joe	NR	62	42	33	36	35
EmergencyPedia	41	30	33	31	26	36
Critical Care Northampton	NR	NR	NR	NR	NR	37
PEM Blog	44	36	37	30	32	38
EM Over Easy	NR	NR	76	62	31	39
60 Second EM	77	70	49	52	40	40
Critical Care Practitioner	43	31	26	21	30	41
EM Curious	39	53	41	40	41	42
Western Sono	62	41	50	37	42	43
NUEM Blog	NR	NR	NR	NR	NR	44
Clinical Monster	NR	85	57	42	44	45
PedEM Morsels	49	46	27	32	34	46
MD Aware	94	92	69	53	48	47
Rogue Medic	48	40	52	43	49	48
Thinking Critical Care	110	130	97	83	52	49
PHARM	40	47	51	55	54	50
Intensive Blog	NR	57	59	45	50	51
The Short Coat	86	102	87	81	58	52
Rolobot Rambles	78	65	73	61	46	53
Emergency Medicine PharmD	152	86	80	66	65	54
GruntDoc	50	45	53	79	51	55
Maryland CC Project	127	141	70	54	75	56
EM in 5	145	75	72	50	62	57
PEM Playbook	NR	NR	NR	NR	NR	58
Rollcage Medic	115	125	116	106	72	59
Trauma Professional's Blog	60	61	63	67	68	60
Emergency Medicine Ireland	55	77	78	82	63	61
EM Sim Cases	NR	106	86	73	69	62
Sask Sonic	126	138	120	80	73	63
ECG of the Week	120	123	129	103	78	64
EMurgucate	88	83	95	70	67	65
Asystole: The Most Stable Rhythm	121	114	124	111	71	66
HQMedEd	79	111	99	85	60	67
Emergency Phenomena	80	66	85	77	79	68

2021 Social Media Index (SMi) Values

The SMi values table demonstrates the Alexa, Facebook, and Twitter values collected for each site for the 2020 SMi.

Website	Alexa	Twitter	Facebook	Social Media Index
LITFL	11458	22100	34267	9.5
EMCrit	222231	64800	69540	7.0
ALiEM	362796	21500	25033	6.2
Rebel EM	431167	26500	19087	6.0
Emergency Medicine Cases	546449	11800	29174	5.8
Dr. Smith's ECG Blog	1053852	27700	69425	5.8
EM Docs	367654	10600	7756	5.7
First 10 EM	286643	11300	3174	5.7
RCEM Learning	448259	17400	2967	5.5
Don't Forget the Bubbles	767565	11700	11121	5.4
EMS 12 Lead	2692513	23800	108451	5.3
WikEM	163198	2619	177	5.2
Core EM	648875	10100	3529	5.2
CanadiEM	736977	13300	3718	5.2
The Skeptic's Guide to EM	1527234	19500	10929	5.1
St. Emlyn's Blog	1404347	24800	4521	5.0
Core Ultrasound	868283	16700	1647	5.0
The Resus Room	1674079	16900	6739	4.9
Ultrasound of the Week	868283	8803	1312	4.8
FOAMcast	2761228	67800	2938	4.8
Intensive Care Network	2662458	15300	8800	4.7
Emergency Medicine Updates	2571763	14700	2507	4.4
EM Basic	2569353	15300	1940	4.4
EM Ottawa Blog	1537161	3986	1843	4.3
Taming the SRU	1528048	4483	1522	4.3
POCUS 101	891328	4579	311	4.3
Journal Feed	954793	1971	777	4.3
FemInEM	8383307	54700	3900	4.2
EM Lit of Note	4896953	14000	3001	4.1
The Gurney Room	643113	766	206	4.0
Resus	3538497	710	5321	3.7
Resus ME	8383307	20400	901	3.7
TotalEM	5731061	1200	2552	3.5
Broome Docs	4091044	8588	86	3.3
Pharmacy Joe	837591	9273	0	3.2
EmergencyPedia	8061681	782	2878	3.2
Critical Care Northampton	934720	9235	0	3.2
PEM Blog	8383307	2295	751	3.2
EM Over Easy	8383307	2132	597	3.1
60 Second EM	8383307	153	4496	2.9
Critical Care Practitioner	1385623	8046	0	2.9
EM Curious	8383307	3187	142	2.9
Western Sono	8383307	2478	166	2.9
NUEM Blog	1561737	4335	0	2.7
Clinical Monster	1415798	2513	0	2.6
PedEM Morsels	2444346	4610	0	2.5
MD Aware	8383307	46200	0	2.4
Rogue Medic	7950870	43	987	2.4
Thinking Critical Care	3790794	5666	0	2.3
PHARM	8383307	23300	0	2.3
Intensive Blog	4984358	7986	0	2.3
The Short Coat	8383307	13300	0	2.1
Rolobot Rambles	8383307	12900	0	2.1
Emergency Medicine PharmD	4065510	2763	0	2.1
GruntDoc	8383307	12200	0	2.1
Maryland CC Project	2757394	1018	0	2.1
EM in 5	3737940	2006	0	2.1
PEM Playbook	6803834	5516	0	2.0
Rollcage Medic	8383307	8021	0	2.0
Trauma Professional's Blog	5728194	3460	0	2.0
Emergency Medicine Ireland	8383307	6621	0	2.0
EM Sim Cases	4162273	692	0	1.8
Sask Sonic	8383307	1578	0	1.7
ECG of the Week	6302541	605	0	1.6
EMurgucate	8383307	1027	0	1.6
Asystole: The Most Stable Rhythm	8383307	861	0	1.5
HQMedEd	8377987	600	0	1.4
Emergency Phenomena	8383307	564	0	1.4

SMI Calculator (Note: Not yet updated with 2021 data)

Formula

The detailed formula for the calculation of the SMi for an individual website is outlined below. Notably, each aspect must be related to the site on the index relative to the other sites highest/lowest Alexa, Twitter, and Facebook numbers:

Feedback?

We would appreciate your assistance in correcting any errors (Did we miss an Alexa Rank, Twitter Account, or Facebook page? Is our data inaccurate?). Feedback on the SMi can also be provided by tweeting @Brent_Thoma.

Updates

There have been numerous updates to the SMi over the years.

2013: Google deprecated the PageRank metric after our original publication¹ and it was no longer be included in future versions of the SMi. Fortunately, our data in the 2013 WestJEM paper suggests that the Alexa score has a high correlation to PageRank. Because of this, we have elected to double the weight of the Alexa score in the SMi calculation to replace PageRank’s contribution. We have also modified the calculation of the Alexa component of the SMi. This change fixes the lowest ranking websites to the lowest value achieved by any indexed site. The effect of this change makes the score more consistent with the other components.

2018: The current formula was shown to correlate with quality.²

2019: Given the time demands of data collection, we transitioned to an annual data collection in December of each year that would be considered the subsequent year’s SMi for each site (e.g. data collected in December of 2019 make up the 2020 SMi).

2020: The inclusion criteria for each website has been clarified. Moving forward, sites already indexed will be retained for the subsequent year if they

Focus on emergency medicine or critical care content
Receive an Alexa score OR have posted content within the last calendar year
Have either a Twitter page (editor- or site-specific) OR Facebook page (site-specific)

Sites will be included moving forward if they are nominated by anyone (tweet any sites meeting the criteria to @Brent_Thoma). To be included they will need to:

Focus on emergency medicine or critical care content
Receive an Alexa score
Have either a Twitter page (editor- or site-specific) OR Facebook page (site-specific)

References

1. Thoma B, Sanders J, Lin M, Paterson Q, Steeg J, Chan T. The social media index: measuring the impact of emergency medicine and critical care websites. West J Emerg Med. 2015;16(2):242-249. [PubMed]

2. Thoma B, Chan T, Kapur P, et al. The Social Media Index as an Indicator of Quality for Emergency Medicine Blogs: A METRIQ Study. Ann Emerg Med. July 2018. [PubMed]