This page describes how The ECG Quiz evaluates user interpretations using a hierarchical scoring system that incorporates Must and Should diagnoses, handles uncertainty, and measures diagnostic accuracy with precision, recall, and F1 metrics. Several case examples below illustrate how the scoring system works.
Interpreting ECGs requires a structured, repeatable approach. Experienced ECG readers use a systematic sequence to ensure that all essential features of the tracing are analyzed. This method helps distinguish objective findings (e.g., QRS presence) from more subjective assessments (e.g., nonspecific T-wave abnormalities). Because ECG interpretation combines both objective and subjective elements, The ECG Quiz incorporates a scoring algorithm that accounts for these differences while providing fair and consistent feedback across all skill levels.
The table below summarizes the standard review sequence used by expert interpreters.
| Step | Component Evaluated | Description |
|---|---|---|
| 1 | Overall Quality | Assess the type and degree of artifact and determine whether artifact interferes with interpretation. |
| 2 | Rhythm | Evaluate regularity, P-wave visibility, and the P–QRS relationship. |
| 3 | Intervals | Measure rate, axis, PR interval, QRS duration, and QT interval. |
| 4 | P Wave Morphology | Assess P-wave width, height, and shape. |
| 5 | QRS Complex Morphology | Evaluate duration, amplitude, and morphological features of the QRS complex. |
| 6 | Pacemaker Activity | Identify pacing spikes, chamber(s) paced, sensing accuracy, and failure to capture or sense. |
| 7 | Miscellaneous Findings | Consider any additional features not covered above (e.g., delta waves, abnormal U waves, strain patterns). |
Historically, ECG experts frequently disagreed when interpreting complex tracings—especially when findings involved borderline abnormalities or subtle repolarization patterns. This natural variability is one reason The ECG Quiz uses a hierarchical and skill-level–based scoring method, ensuring that users receive appropriate credit and feedback, whether the finding is objective or somewhat subjective.
To accommodate learner variability, The ECG Quiz classifies each required diagnosis for an ECG as either:
A Beginning Learner may only be expected to identify “Supraventricular Tachycardia,” while Intermediate and Advanced learners are expected to specify the mechanism, such as:
These Must/Should assignments vary by skill level and by each individual ECG.
The ECG Quiz also uses a hierarchical diagnosis system, in which:
This hierarchical structure allows learners to receive appropriate credit when identifying more specific—or less specific—diagnoses depending on their skill level.
The ECG Quiz uses a standardized set of scoring terms to compare your interpretation with the correct interpretation. Each diagnosis you submit is categorized using the following definitions.
| Term | Definition |
|---|---|
| True Positive (TP) | A diagnosis you include that is also present in our interpretation. |
| False Positive (FP) | A diagnosis you include that is not present in our interpretation. |
| False Negative (FN) | A Must diagnosis in our interpretation that you fail to include, unless a more specific diagnosis within its hierarchy is present. |
| True Negative (TN) | A diagnosis you do not include that is also absent from our interpretation. |
| Not Counted (NC) | A diagnosis included in your interpretation but excluded from scoring due to hierarchical rules or because it is a Should diagnosis you omitted. |
| Duplicate Entry | A repeated diagnosis in your interpretation; duplicates are ignored for scoring. |
| Not Graded | A diagnosis present either in your list or ours that is not used for scoring this ECG. |
These terms form the basis for calculating:
These metrics ensure fair, consistent feedback across all skill levels.
Because ECG diagnoses form a hierarchy of general → specific patterns, the scoring system adjusts outcomes depending on which diagnoses you include.
These adjustments prevent users from receiving double credit or unfair penalties.
If you omit a Must diagnosis but include a more specific Should diagnosis on its hierarchy:
Example: An ECG shows *Atrial Flutter with 2:1 Block*. At Beginner level:
If you enter *Atrial Flutter with 2:1 Ventricular Response*, you receive a TP, and the Must (*Atrial Flutter*) becomes NC because you selected the more specific diagnosis.
If you omit the Must and include a specific diagnosis that is in the hierarchy but not in our Must/Should lists:
Example: Entering *Atrial Flutter with Variable Response* instead of *Atrial Flutter with 2:1 Response*:
You correctly identified *Flutter* but not the specific pattern.
If you include both a general Must diagnosis and a more specific Should diagnosis:
This prevents double credit for overlapping diagnoses.
Example: Beginners analyzing a narrow-complex tachycardia:
Entering *both* yields:
You get credit for the more specific diagnosis.
You may reread ECGs as many times as you wish. Your statistical summary tracks performance trends for:
You may archive your current results to reset your statistics at any time.
Good luck, and have fun interpreting ECGs!