This article explains the algorithm for calculating the Proctoring Credibility Score.
For each proctoring session, the system can calculate the average percentage violation for the following metrics:
- Focus changed to a different window (b1)
- Full-screen mode is disabled (b2)
- Webcam is disabled (c1)
- Face invisible or not looking into the camera (c2)
- Atypical keyboard handwriting (k1)
- Microphone muted or its volume is low (m1)
- Conversation or noise in the background (m2)
- No network connection (n1)
- Screen activities are not shared (s1)
- Several faces in front of the camera (c3)
- Face does not match the profile (c4)
- Found a similar profile (c5)
- No connection to a mobile camera (n2)
The list of metrics considered for the final credibility score is defined on the proctoring session template level. Also, on the proctoring session template level, the weighting coefficient for each metric can be assigned (default weight is 1). With the weighting coefficients, the influence of each metric on the final result can be fine-tuned.
The credibility score for the proctoring session is calculated using the following formula:
where E ∈ [0, 100] is the credibility score (if E < 0, then E = 0), xk is the session-averaged value of the metric k, wk is the weighting coefficient of the metric k, M ∈ {b1,b2,c1,c2,…} are the metrics.
The system automatically grades each proctoring session based on the credit score E and the threshold T parameter if the auto conclusion is enabled.
The threshold T is defined on the proctoring session template level.
If E < T for the proctoring session, the system automatically assigns a negative conclusion to the proctoring session.
Otherwise, the system assigns a negative conclusion.
How it works:
- For each violation, the system measures how long the violation lasted during the session and converts it into a percentage of the total session time.
- Each violation percentage is multiplied by its assigned weight.
- All weighted violations are summed.
- This sum is subtracted from 100 to produce the credibility score (in %).
Note: Violations with higher weights have a greater impact on the credibility score. Using very high weights can cause the score to drop significantly, even if the violation occurred for only a short period of time
Simple Example
Suppose we have a session that lasts 60 minutes. The violations and the percentage of the session during which they occurred can be calculated as follows:
- b1 violation: happened for 12 minutes: b1=12/60⋅100%=20%
- b2 violation: happened for 6 minutes: b2=6/60⋅100%=10%
- c1 violation: happened for 3 minutes: c1=3/60⋅100%=5%
The weights assigned to these violations are:
- wb1 = 0.5
- wb2 = 2
- wc1 = 1
Then, the credibility score is calculated as follows:
100−(wb1⋅b1)−(wb2⋅b2)−(wc1⋅c1)=100−0.5⋅20−2⋅10−1⋅5=100−10−20−5=65%
Conclusion: The higher the weight of a violation, the greater its impact on the credibility report.
