Here are some of the details you’ll need to gather for how each paper reports the outcome:
How do the study authors define the outcome? For example, what counts as “severe bleeding?”
How is the outcome measured? For example, is it a count, a category, or a continuous measure?
What units were used to measure the outcome? For example, pounds or kilograms? Inches or centimeters?
What scales were used to measure the outcome? For example, depression, quality of life and other patient reported outcomes are often measured using some type of scale. Be sure to check to see if the scale used has been validated, in other words, is there scientific proof that the scale measures what it’s supposed to measure?
Who determined that this outcome happened? For example, a nurse? A doctor? The patient?
How was the information about this outcome collected? For example, through blood tests? Observation? A survey?
When was the information about the outcome collected? For example, at the time of care? Six months later? Years later?