Full Detailed In-Depth Explanation:

In Oracle Global Human Resources Cloud, the compa-ratio (comparison ratio) measures an employee’s salary against the midpoint of a grade rate range. It’s displayed in the employment or salary details section when entering a base salary, provided all components are correctly aligned.

Option A: Incorrect. Grade rates and salary basis don’t need to share the same legislative data group (LDG) for compa-ratio calculation; LDGs partition data but don’t directly affect this display unless misconfigured at a higher level.

Option B: Incorrect. The grade itself isn’t tied to an LDG; it’s the grade rate that matters. This option misattributes the relationship.

Option C: Incorrect. While frequency (e.g., monthly vs. annual) must align for accurate salary calculations, compa-ratio is normalized and should still display if the grade rate and salary basis are linked, even with frequency differences (assuming conversion is handled).

Option D: Correct. The compa-ratio requires a grade rate (defining min, mid, max values) to be associated with the salary basis used in the employee’s record. If the grade rate isn’t linked to the salary basis (via "Manage Salary Basis" or "Manage Grade Rates"), the system lacks the reference range to compute and display the compa-ratio. This is a common setup oversight during implementation.

The correct answer isD, as detailed in "Using Global Human Resources" on salary management and grade rate integration.