Dissemination of Findings Fast Using Online-videos Trial
Dissemination of Findings Fast Using Online-videos Trial
The investigators will conduct a two-arm, randomized controlled trial of the effect of
 emotional content in online videos on the extent to which the video is disseminated
 (forwarded). Dissemination can be assessed in terms of the number of views which can increase
 as a result from sharing and forwarding of the video.

 In this study, an experiment video and a control video, both of which are approximately 2.5
 minutes long, will be uploaded on YouTube, the most visited video sharing website. The videos
 concern the WOMAN trial, a large RCT of tranexamic acid in postpartum hemorrhage. The
 experimental group will receive a video with strongly emotional content (an interview with a
 postpartum hemorrhage survivor and her husband). The control group will receive a short video
 in which a researcher conveys the same information (but without the first hand experience of
 the survivor and her husband). Otherwise, the two videos are identical.

 Participants, selected from clinicians and researchers in obstetrics and gynecology, will be
 randomly allocated to two groups. An e-mail with a link to either of the videos will be sent
 to the participants. In the e-mail, they will be asked to watch the video and forward the
 link to their colleagues if they find it helpful.

 The primary outcome is video forwarding. The secondary outcome is the number of access to the
 video that each participant generated.

 Data will be collected for 14 days after the e-mails are sent to the participants. The
 relative risk (RR) of forwarding the videos will be calculated as effect measure and compared
 using chi-square test. The distribution of the numbers of access to the video that each
 participant generated will be compared using Wilcoxon signed-rank test.

 The hypothesis is that an online video with emotional content has higher chance of being
 forwarded to other people and therefore, gets higher number of views than an less emotional
 online video.
[Statistical analysis plan for the DIFFUSION trial]

 SETTING

 Two videos will be uploaded on YouTube through a new account created for this study. The
 uploaded videos will be embedded in two independent websites with white background. A
 computer programme has been created to collect the data of access to the videos.

 International journals in obstetrics and gynaecology published in 2013 and 2014 will be
 sought for participant recruitment. The authors of the articles published in the journals who
 met the inclusion criteria will be assigned ID numbers and randomised to receive either the
 intervention or control video. Randomised participants will be sent a unique web address
 (URL) of the video that they are allocated to by e-mail via a mass e-mailing service,
 Campaign Monitor. Each URL will be linked to the participant's ID number in the database.
 They will be asked to watch the video and forward it to their colleagues if they find it
 helpful. If a randomised participant forwards their URL to another person, and that person
 clicks on it, the click will be recorded against the participant's ID number in the computer
 programme. Therefore, if there are multiple accesses from the same ID number, it is either
 because the participant watched the video more than once or because the participant forwarded
 the URL and other people watched the video.

 This trial will be coordinated from the London School of Hygiene & Tropical Medicine
 (University of London) and conducted worldwide online.

 SAMPLE SIZE AND STATISTICAL POWER

 Two main factors determine the number of patients needed in a trial. These are the estimated
 event rate and size of the treatment effect. The investigators will power the trial for our
 main outcome: percentage of participants that forwarded the video at least once in each arm.

 ESTIMATED EVENT RATE: Based on other studies, baseline e-mail forward rate was assumed to be
 10%.

 SAMPLE SIZE AND SIZE OF INTERVENTION EFFECT THAT SHOULD BE DETECTABLE: Assuming the change
 from baseline is 7.5% (75% increase from 10% to 17.5%), the sample size required for this
 study was calculated. The calculation suggested 1000 participants, 500 per group, are
 required to test the null hypothesis at the 5% significance level with 90% power. We learnt
 from the pilot trial that around 14% of e-mail recipients click on the link and watch the
 video. In order to get 1000 participants to watch the videos, 7000 participants will be
 required given the video viewing rate of 14%.

 CRITERIA FOR EVALUATION

 All participants randomly assigned to one of the videos will be analysed together, regardless
 of whether or not they watched the video, on an intention to treat basis. This analysis is to
 examine the effect of the intervention in a practical scenario. In addition, only those who
 watched the videos will be analysed on a per-protocol basis to estimate the efficacy of the
 intervention.

 RANDOMISATION

 An independent statistician will randomly allocate the ID numbers of the participants to
 either the intervention or the control groups using a computer programme. Allocation will be
 concealed to a person who will recruit participants. Randomisations were balanced 1:1.

 BLINDING AND UNBLINDING

 As two videos are apparently different, participants cannot be blinded in this trial.
 However, each participant is not sent the other video so in principle they cannot tell if
 they received a video with more or less emotional content. The study coordinator who will
 conduct data analyses is masked to the allocation. The data will be unblinded after this SAP
 is submitted to the ClinicalTrial.gov and all data analyses have been completed. The data are
 kept in a password-secured online archive (Google drive). Access to the data is limited to
 the trial coordinator and technical assistant who developed the computer programme for data
 collection.

 ANALYSIS PRINCIPLES FOR FINAL ANALYSIS

 -  Two different analyses will be conducted for the primary outcome on an
 intention-to-treat basis and a per-protocol basis.

 -  All tests will be two-sided, and the nominal level of α will be 5% for the main
 analysis.

 -  All statistical analyses will be unadjusted except where indicated.

 -  Missing values will not be imputed unless specified otherwise. Where the number of
 missing observations is substantial, the number of observations used in the analysis
 will be reported.

 -  P values will not be adjusted for multiplicity. However, the outcomes are clearly
 categorised by degree of importance (primary and secondary).

 DATA COLLECTION AND OUTCOME ASSESSMENT

 Every time someone clicks on a URL to access a video our computer program collects four
 variables: (a) ID number (b) IP address from which the URL is clicked, (c) date and time of
 access (recorded in Great British Time regardless of the country of the IP address) and (d)
 type of device (web browser, phone or computer device)

 Definition of access by the same person to a video:

 As there is no way to detect forwarding, accesses to the video by unique individuals will be
 counted as the closest indicator of forwarding. It is also impossible to precisely
 distinguish an access by a unique individual, in other words, to tell if the video was
 accessed more than once by the same person or by different people. Therefore, the
 investigators need to make assumptions based on the data collected by our programme. In the
 main analysis, the investigators will consider that accesses with the same ID number from the
 same IP address mean that a person watched the video more than once. Accesses with the same
 ID number from different IP addresses will be considered as accesses by unique individuals.
 The data of the other variables (time and type of device) will be considered in the
 sensitivity analysis. Multiple accesses with the same ID from the same IP address within five
 minutes will be counted as one access, allowing for the possibility that a person watched the
 video more than once because the video did not play the first time or the parson wanted to
 confirm the information in the video.

 CHARACTERISTICS OF PARTICIPANTS AND BASELINE COMPARISONS

 Description of the baseline characteristics listed below will be presented by intervention
 group. The countries which the participants are based in were categorised into low, middle
 and high income countries based on the classification by the World Bank. Discrete variables
 will be summarised by frequencies and percentages. Percentages will be calculated according
 to the number of participants for whom data are available. Where values are missing, the
 denominator (which is less than the number of patients assigned to the treatment group) will
 be stated in either the body or footnote of the corresponding summary table.

 Continuous variables will be summarised using standard measures of central tendency and
 dispersion, i.e. either a mean or a median with SD.

 DESCRIPTION OF ANALYSES

 The outcome assessor will be masked to the identity of each participant by using ID numbers
 instead of individual names or e-mail addresses.

 Accesses to the videos will be counted as a substitute for the measure of forwarding.
 Therefore, even if a participant forwarded the URL to another person, if the person does not
 click on the link, that forwarding will not be counted. This leads to the underestimate of
 the effect of the intervention.

 PRIMARY OUTCOME: A standard chi-square test will be used as the primary test of statistical
 significance of the effect of intervention allocation on the proportion of video forwarding.
 Frequencies and percentages per arm, and a risk ratio measuring the intervention effect and
 its 95% confidence interval (CI) will also be reported.

 SECONDARY OUTCOMES: Distribution of number of accesses generated by each participant will be
 compared. The difference in the means (SD) in each arm will be estimated in order to assess
 the effect of the intervention along with the P value. To test the statistical difference in
 distribution, Wilcoxon signed-rank test will be conducted. In case the distributions are
 complex, the data will be stratified into a few groups and chi-square test will be conducted
 to test the statistical difference in distribution.

 After assessing the distributions, a t-test and Mood's median test will be conducted to test
 the statistical difference in the mean and median of the number of access to the videos that
 each participant generated respectively.

 SENSITIVITY ANALYSES: The effect of the intervention may vary according to the definition of
 an access by a unique person. Therefore, the investigators will conduct sensitivity analyses
 for all outcomes using two different definitions of an access by a unique person: most
 conservative definition and most liberal definition.

 The possible largest effect of the intervention and the difference in all the outcomes
 between the two groups will be estimated using the most liberal definition of forwarding.
 Likewise, the possible smallest effect of the intervention and the difference in all the
 outcomes between the two groups will be estimated using the most conservative definition.
 With the most liberal definition, the investigators will count all accesses as those by
 different persons. With the most conservative definition, the investigators will count
 accesses as those by different persons only if the data from all the categories are
 different.
Inclusion Criteria:

 -  Clinicians and researchers in obstetrics and gynaecology who have an e-mail address.

 Exclusion Criteria:

 -  Clinicians and researchers who are in the countries where YouTube cannot be accessed
 (China, Iran, Pakistan and Turkmenistan).