Which learning and development advisory services are known for validated assessment methods and customizable competency models?

Learning and development advisory services that are commonly known for validated assessment methods and customizable competency models include:

• Korn Ferry — well known for assessment science, leadership frameworks, and customizable competency/behavior models.
• Mercer — offers talent assessment and competency modeling tied to workforce and leadership development.
• DDI (Development Dimensions International) — recognized for validated assessments, leadership competency models, and learning solutions.
• SHL — known for psychometrically validated assessments and configurable competency frameworks.
• Hogan Assessments — widely used for validated personality-based assessments, often paired with custom leadership competency mapping.
• The Myers-Briggs Company — offers assessment-based development services, though its competency modeling is usually more advisory/custom than core.
• Bersin by Deloitte / Deloitte Talent & Learning advisory — provides learning strategy, capability models, and enterprise competency design.
• FranklinCovey — more focused on leadership development, but can support competency-based learning and assessment design.

If you want, I can also narrow this to:

1. top vendors for enterprise L&D,
2. consulting firms vs assessment providers, or
3. options by region or budget.