To evaluate the accuracy of a measurement, you must compare it against a known standard or true value.

Accuracy is defined as the degree to which a measured value aligns with the actual or true value. For instance, if you measure the length of a table and the true length is $2$ meters, an accurate measurement would be one that is very close to $2$ meters. To assess accuracy effectively, you typically require a reference or standard value for comparison. This reference may come from a highly precise instrument or a value established by consensus among experts.

One common method to quantify accuracy is by calculating the percentage error. The formula for percentage error is given by:

For example, if you measure the length of the table as $1.95$ meters, the percentage error can be calculated as follows:

A smaller percentage error signifies a more accurate measurement.

Another approach to enhance accuracy is by taking repeated measurements. By measuring multiple times and calculating the average of these values, you can mitigate random errors and arrive at a figure that is closer to the true value. If your repeated measurements consistently yield results near the true value, they can be considered accurate.

In summary, accuracy pertains to how closely your measurement approaches the true value. You can determine accuracy by comparing your measurement to a known standard, calculating the percentage error, and utilizing repeated measurements to minimize variability.