Not every piece of technology measures data in the same way. This is something to consider when analyzing information and using different types of tech.
Primarily, there are two ways data points might be computed, and they are classified as either “Observed” or “Inferred”.
Observed v. Inferred
An observed data point is a metric that is “precisely measured”. An example of this would be using a measuring tape to record how far a hit baseball traveled. It’s direct, largely accurate with the error rate being very low.
Not every metric on baseball technology is measured like this. Because some pieces of tech are limited in their ability to measure everything precisely, some data points are “estimated” or “projected.” This is what we call an “inferred” data point.
An example of this would be similar to estimating home run distance using numbers like launch angle, exit velocity, and air time. It’s likely you’ll get a close estimation of what the distance was, but it will not be as exact as measuring it from home plate to where the ball landed.
Baseball Technology
Inferred and Observed data points are mostly discussed as it pertains to Trackman or Rapsodo ball-tracking technologies.
Trackman uses a 3D doppler radar system to track a baseball in flight. It can measure precisely the movement and spin of the ball. Those are its “observed” data points. But, it uses the movement numbers to calculate or project its “Tilt” metric. That is an “inferred” data point.
Conversely, Rapsodo takes images of pitched baseballs at ball release to calculate its data points. It can “observe” Spin Axis and Efficiency, but it uses those numbers to “project” vertical and horizontal movement.
Examples of Observed data points:
Trackman: Vertical and Horizontal Movement
Rapsodo: Spin Axis and Spin Efficiency
Examples of Inferred data points:
Trackman: Tilt
Rapsodo: Vertical and Horizontal Movement
Summary
Keep in mind which metrics on certain baseball technologies are observed or inferred. As you analyze data it’s crucial to understand how each metric is calculated because every piece of information should always be taken within the right context.
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