Visual estimates of blood loss by medical laypeople: Baseline data

SND-ID: 2020-42

Creator/Principal investigator(s)

Erik Prytz - Linköping University orcid


The data material was collected in a controlled experiment that investigated the ability of laypeople to visually assess blood loss and to examine factors that may impact accuracy and the classification of injury severity. A total of 125 laypeople watched 78 short videos each of individuals experiencing a hemorrhage. Victim gender, volume of blood lost, and camera perspective were systematically manipulated in the videos.



Research principal, contributors, and funding

Research principal

Linköping University

Responsible department/unit

Department of Computer and Information Science


Mattias Lantz Cronqvist - Linköping University, Department of Computer and Information Science

Rachel Phillips - Old Dominion University, Department of Psychology

Marc Friberg - Linköping University, Center for Disaster Medicine and Traumatology

Carl-Oscar Jonson - Linköping University, Center for Disaster Medicine and Traumatology, and Department of Biomedical and Clinical Sciences


  • Funding agency: Swedish Civil Contingencies Agency
Protection and ethical review

Data contains personal data


Method and time period

Unit of analysis


Medical laypeople (undergraduate students at an american university)

Study design

Experimental study

Sampling procedure

Participants took part in a controlled experiment in which they viewed a series of 78 five-second film clips featuring a person with a simulated bleeding. They were asked to, as quickly as possible, classify the video as showing a life-threatening or not life-threatening bleeding using a keyboard response. After each video, the participant was asked to estimate how large the bleeding was, classify the severity of the injury, and, if they classified the video as showing a life-threatening bleeding, to estimate how minutes it would take for the victim to die from their bleeding. The participants also completed a basic demographics questionnaire at the end of the experiment. The entire experiment took between 40 to 60 minutes to complete.

The participants were students at a large south-eastern university in the USA. Participants with prior medical training or stop the bleed education were excluded. Thus, all participants were medical laypeople without prior experience.

The variables varied in the videos were victim sex (male or female), blood volume (ml of blood on the floor), and rate of blood flow (in ml per minute). Further, two video sets were created, one with a top-view (camera placed above the victim) or front view (camera placed facing the victim from the front). In each video, the victim was dressed in blue, hydrophobic scrubs and were seated against a white wall. The simulated wound was not visible. The actors were positioned such that the blood flowed down their thigh and pooled between their legs. The same male and female patient actor were used for all videos. The flow rates used were 80, 200, and 400 ml/minute. The blood volumes used were 0, 50, 100, 150, 200, 300, 400, 500, 700, 900, 1100, and 1900 ml. The combination of three flow rates, 13 blood volumes, and two genders meant that there was 78 videos in total.

For the current dataset, the data has been collapsed across flow rate, and the volume 0 has been excluded, meaning that there are 24 combinations (2 genders x 12 volumes). The dataset includes the response time for the initial classification, the classification response, the volume estimate, and the volume error (calculated as the difference between the true amount and the estimated amount of blood loss).

Time period(s) investigated

2019-08-01 – 2019-12-31

Geographic coverage
Visual estimates of blood loss by medical laypeople: Baseline data

Associated documentation


The data set consists of four variables: volume estimate, volume error, response time, and classification.

Each variable has a separate sheet in the excel document.

The data is from 125 individuals, each listed on a separate row with a unique ID for each individual.
Each sheet includes the participant ID (anonymous number), age in years, participant sex (0 = male, 1 = female), perspective of the video clip (0 = top view, 1 = front view), and then one column for each victim gender and loss volu

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Version 1


Erik Prytz. Linköping University (2020). Visual estimates of blood loss by medical laypeople: Baseline data. Swedish National Data Service. Version 1.

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Data format / data structure


Creator/Principal investigator(s)

Erik Prytz - Linköping University orcid

Data collection

  • Mode of collection: Laboratory experiment
  • Time period(s) for data collection: 2019-08-01–2019-12-31
  • Source of the data: Research data: Unpublished



Number of individuals/objects


Published: 2020-10-06
Last updated: 2020-10-07