Why rate medical calculators?
MDCalc is synonymous with the best, most usable medical calculators and clinical decision tools. Our inclusion criteria for scores and medical research published on MDCalc are strict, and we frequently do not proceed with calculator development if the available evidence for a score is insufficient to support its clinical use, or if it is impractical or not useful in helping guide management.
While we are staunch proponents of the “E” in EBM, we understand the limitations of evidence in the clinical setting. We know that not every diagnostic score can be validated in hundreds of thousands of patients, and not every treatment has a large-scale RCT backing it. (See: BMJ 2003, Parachute use to prevent death and major trauma related to gravitational challenge: systematic review of randomised controlled trials.)
Keeping this in mind, we occasionally will review a score and find its evidence less substantial than other scores (perhaps lacking external validation, for example), but still include it on MDCalc if we find it is clinically useful and is based on the best available evidence.
Our aim in providing MDCalc Ratings is to provide useful information on the quality and usability of a calculator in a single easily-understood rating.
What are the methods?
With the above in mind, we have developed the MDCalc Ratings system. The MDCalc Rating is a weighted average of three components: Clinical Utility (“Clinical”), Strength of Evidence (“Evidence”), and Popularity, with Clinical and Evidence ratings weighted more heavily than Popularity.
Each component is assigned a rating between 1 and 5, with 1 being the weakest and 5 the strongest.
Clinical Utility is a subjective rating assigned by an MDCalc rater: a practicing physician who uses the calc. The Clinical Utility of a calculator summarizes how useful it is in the “real world” for taking care of patients. Raters are asked to consider the following:
A note on the number of inputs: Having fewer inputs, or simpler equation logic, or another “traditional” measure of ease of use by itself should NOT increase the Clinical rating, especially if it sacrifices accuracy. However, raters should use their judgment and common sense: if Score A and Score B are otherwise equal but Score A requires 30 inputs and is 97.5% sensitive for Disease X, but Score B requires 3 and is 97.2% sensitive, it is reasonable to rate Score A higher for utility. Clinical decision tools have traditionally been thought to be more “usable” if they’re easy to memorize, but that’s a philosophy more applicable in a time before computers and MDCalc!
The Strength of Evidence rating is assigned as follows:
There are several grading systems for quality of evidence that have been published. We’ve chosen this one because it is clear, concise, easy to understand, and seems to be the most clinically applicable.
The Popularity rating is dynamically generated based on user traffic to the calc page and updated every 6 months. For calcs on MDCalc less than 6 months, the suffix “p” will be attached to the Clinical/Evidence rating (e.g. 4p = Clinical/Evidence rating 4, Popularity rating pending).
Who rates the calcs?
Calcs are rated by at least two practicing physicians in a specialty relevant to the calc. Calc ratings are re-evaluated annually at minimum, and more frequently as needed (e.g. if new validations or meta-analyses are published).
I disagree with a rating.
I’d like to help rate calcs. How can I get involved?
MDCalc raters are practicing doctors who have used a calculator clinically. To apply to be a rater, please email your CV to email@example.com with “MDCalc Ratings” as the subject.
What are the limitations of MDCalc Ratings?
As is true in general with our calculators, these ratings aren’t meant to be prescriptive, and just because a calculator has a high rating, doesn’t mean you should always use it (and conversely, if a calc has a low rating doesn’t mean you should never use it). Always make sure you are applying a score to the right patient to answer the right question (our When to Use section can help, and detailed inclusion criteria and evidence appraisals are found in the Evidence section where applicable), and above all, use your clinical judgment when using decision tools to help manage patients.