Examples: Standard deviation (for a Gaussian response function), full width at half maximum intensity (for any bell-shaped distribution), and decay length (for an exponentially increasing or decreasing region of the response function).

Notes:

1. Standard deviations can be used for any bell-shaped curve. If parameters are measured for a step change in composition, care must be taken that the depth range for the measurements is large enough to ensure that the signal becomes constant with depth on either side of the step.
2. Parameter definitions should be used consistently.
3. Depth resolution parameters usually give no indication of distinguishability, but are useful in instrumental evaluation and profile deconvolution.