Why is the Advanced Whole-Body Assessment scoring different from Manual Whole-Body Assessment scoring?
The observation-based Manual Whole-Body Assessment (WBA) and the motion-capture based Advanced Whole-Body Assessment are separate assessment tools. They both provide measures of risk for musculoskeletal disorders within jobs. While both tools are based on 100-point scales of risk and consider the same 9 body areas, the differences in how scores are calculated can result in substantial differences in both individual body area and overall risk scores between the two methods. Thus, the scores can’t be directly compared.
Motion capture gathers continuous data throughout a task to simultaneously measure posture, frequency, and duration while leveraging machine learning to constantly improve data quality. The Advanced Assessment provides multiple thresholds for force categories to more accurately assess the different ways force is exerted in the workplace. These increased levels of fidelity in the Advanced Assessment also apply to the severity of the posture and the extent of duration exposure.
In short, Advanced Assessments assess tasks with more accuracy and detail than Manual Assessments.
Key differences between the Advanced WBA and the Manual WBA
1. Body segment score and threshold categories are different.
The body segment Risk Rating scores (left hand/wrist, right hand/wrist, neck, etc.) are calculated differently in the Advanced Assessment versus the Manual Assessment. For example, an exposure to high forces on the shoulder can result in a maximum score of 1 using the Manual Assessment; however, using the Advanced Assessment, that score could range from 0 to 4. The resulting Risk Rating score totals for each of the 9 body segments will therefore be different for the two methods.
Body segment Risk Rating scores, Manual Assessment:
Body segment Risk Rating scores, Advanced Assessment:
2. The primary musculoskeletal disorder (MSD) risk factors are weighted differently.
With the Advanced Whole-Body Assessment, force is weighted the highest and the assessment takes the direction of movement into account. The Manual Whole-Body Assessment weighs force, posture, and duration equally.
3. Duration and frequency calculations are performed differently.
The Advanced Assessment calculations are based on the percent of time spent in the awkward posture, which is why we recommend videos be around 30 seconds in length. The calculations done by the Advanced Assessment are more accurate than the simplified single threshold for force and posture represented by the Manual Assessment.
4. Different secondary MSD risk factors affect the Risk Priority Score (RPS).
Based on current research, the Advanced Whole-Body Assessment only factors in vibration, which contributes up to 1% of the total RPS.
The Manual Whole-Body Assessment includes vibration, impact stress, and glove issues, but this leads to high variability due to subjective inputs, although it contributes up to 10% of the total RPS.
How do I interpret the Advanced Assessment results?
Due to the additional information that motion capture technology provides, the Advanced Assessment overall Risk Priority Score has more “bands” of risk.
Risk Priority Scores, Manual assessment:
Risk Priority Scores, Advanced assessment:
See How does the Industrial Ergonomics software calculate risk? for more details.
What if I have been using the Manual Assessment and Risk Priority Score?
That’s great! You do not need to re-do your assessments and all your historical data will remain in Industrial Ergonomics. Simply begin using the Advanced Whole-Body Assessment for all future risk assessments. There may also be tasks where you are unable to complete an Advanced assessment (for example, when a video isn’t permitted for security reasons). In those cases, it is appropriate to complete a Manual Assessment.
