Based on the provided process variants and their performances, here are some process and data-specific considerations that might contribute to performance issues:

1. **Rejections and Iterations:**
   - Many process variants involve multiple rejections and resubmissions, leading to increased processing time and reduced performance. For instance:
     - Variant 345, 188, 36, 29, 11, 6 (multiple rejections by ADMINISTRATION and EMPLOYEE)
     - Variant 77, 49, 20, 14, 6 (multiple rejections by SUPERVISOR and EMPLOYEE)
     - Variant 57, 8 (multiple rejections by PRE_APPROVER and EMPLOYEE)
   - *Root cause:* Inefficient initial submission, poor approval criteria, or lack of clear communication leading to unnecessary rejections.

2. **Involvement of Multiple Approvers:**
   - Some variants involve multiple approvers, which can increase processing time and delay final approval. For example:
     - Variant 2473, 188, 36, 29, 10 (involvement of BUDGET OWNER)
     - Variant 575, 57, 8 (involvement of PRE_APPROVER)
   - *Root cause:* Complex approval hierarchy or unnecessary approval steps.

3. **Missing Information (MISSING rejection):**
   - Variants 40 and 21 involve rejections due to missing information, leading to resubmission and additional processing time.
   - *Root cause:* Incomplete initial submission or lack of clear guidelines on required information.

4. **Long Processing Times for Some Variants:**
   - Some variants have significantly higher performance (processing time) than others. For example:
     - Variant 1392 (854633.975) vs. Variant 4618 (810187.903)
     - Variant 575 (861058.409) vs. Variant 4618 (810187.903)
   - *Root cause:* Complexity of the declaration, additional checks, or specific requirements for certain variants.

5. **Low Frequency of Some Variants:**
   - Some variants have a low frequency (e.g., 7, 8, 10, 14, 20, 29, 31, 36, 40, 49, 57, 6, 77), which might indicate that they are not well-defined or not commonly used, leading to inefficiencies.
   - *Root cause:* Lack of clarity in process definition, infrequent use, or unnecessary complexity.

To improve performance, consider streamlining the process by reducing unnecessary rejections, simplifying approval hierarchies, providing clear guidelines for initial submissions, and reviewing low-frequency variants to ensure they are still necessary and well-defined.