Fueling growth across the entire leadership pipeline for more than 55 years.
With DDI, organizations build better leaders who deliver results. We rethink what’s possible, turn leadership into your competitive edge, and empower HR to lead as strategic business partners.
Our Story
Pioneering Leadership Solutions
Founded more than 50 years ago, Development Dimensions International® (DDI) set out to transform how the world hires, develops, and promotes leaders by combining scientific rigor with practical application.
Since 1970, we’ve helped organizations turn leadership into their strongest competitive advantage—developing leaders who deliver measurable business impact and empowering the HR teams who make it happen.
Why DDI
What Makes DDI Different
Why do the world’s leading companies trust DDI? Because we’re the only partner who transforms leadership across the entire pipeline, from the frontline to the C-suite. Our track record speaks for itself—we bring that expertise to every partnership as an extension of your team.
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Leadership pipelines that deliver results.
We help organizations build leadership pipelines that drive long-term growth and the results that matter most to your business.
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Integrated Approach
Our unified approach identifies who’s ready to lead, builds the capabilities they need, and provides the experiences that accelerate growth.
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Proven Expertise
Backed by decades of behavioral science and research, our proven approach helps you make confident talent decisions and predict leader performance with precision.
What We Do
Leadership That Delivers Results.
The right leaders carry your business forward. But only when they have what they need to succeed. Our complete, flexible solutions help you hire with confidence, develop effective leaders, and build ready-now pipelines so your people can thrive while delivering measurable results.
Interviewing
Transform interviews into your competitive edge with a structured, science-backed approach that delivers better hires, faster.
Learn MoreAssessment
Stop guessing. Start knowing. Get the objective insights that reveal both potential and readiness to perform.
Learn MoreDevelopment
Transform your leaders into confident, high-impact decision-makers—with insights and tools that drive real change.
Learn MoreSuccession
Assess, grow, and sustain your talent bench with strategies that accelerate readiness and ensure long-term resilience.
Learn MoreWe’ve spent decades refining exactly what it takes to create real behavior change. Now it’s your turn to see what better leadership can do for your organization.
Industry Leaders
Meet our Leadership Team
Our leaders bring unmatched expertise and a shared passion for helping our clients build better leaders every day.
Tacy M. Byham, Ph.D.
Chief Executive Officer
As DDI's Chief Executive Officer, Tacy oversees the organization’s day-to-day operations and is spearheading increased strategic focus on DDI's core of leadership insight and growth.
David Tessmann-Keys
President
President David Tessmann-Keys is responsible for developing and executing DDI’s global business strategy and leading all components of the company’s global operations across the Americas, EMEA, Greater China, and Asia Pacific.
William C. Byham, Ph.D.
DDI Founder and Executive Chairman
Bill is Cofounder and Executive Chairman of DDI and works to establish the vision, values, and strategic direction of the company. He supervises major DDI product development and consulting projects.
Jazmine Boatman, Ph.D.
Senior Vice President, North America and European Operations
Jazmine believes passionately in the mission of building better leaders and is responsible for the business strategy and execution for DDI’s U.S. market.
Kelli Buczynski
Chief People Officer
Kelli is responsible for the execution of DDI’s people and culture strategy around the world.
Verity Creedy
Sr. VP, Product
As an SVP of Product with two decades of expertise in the HR industry, Verity thrives on transforming customer insights into strategic product developments. Verity's commitment to understanding customer needs allows her teams to build solutions that not only meet expectations but also elevate the leader's experience.
Joni Murello
Vice President, General Counsel
Joni manages all DDI’s legal, regulatory, and contractual compliance globally.
Steve Runkel
Sr. VP, Global Sales Strategy & Marketing
Steve plays a key role in developing DDI’s international sales and go-to-market strategy, as well as leading DDI’s U.S. sales team.
Julie Simmons
Chief Information Officer
As Chief Information Officer, Julie Simmons leads DDI's global technology strategy for its suite of leadership products as well as its internal data and systems infrastructure.
Patsy Tsao
Senior Vice President and Chief Financial Officer
Patsy is responsible for the administrative, financial, and risk management operations of the company worldwide.
Mindy Yeh
Senior Vice President, Asia
Mindy leads DDI's business strategy and operations in the Greater China region, including Hong Kong, Mainland China, and Taiwan.
Don’t take it from us. DDI is consistently recognized for leadership innovation, proven solutions, and lasting results.
Culture & Careers
Find Your Future Here
At DDI, we’re powered by people who believe in our mission—and supported by a culture that helps everyone thrive. We’re built on collaboration, curiosity, and growth, creating real opportunities to learn, lead, and shape the future of leadership. Our commitment to being an exceptional workplace earned us recognition on Forbes' 2024 and 2025 list of America's Best Midsize Employers.
Trusted Globally
Chosen by the World’s Top Organizations
Leading companies around the world trust DDI because we understand what’s at stake. Your leaders determine whether strategies succeed or stall. We help you transform leadership from your biggest question mark into your strongest competitive advantage. Discover how we help organizations like yours build leaders ready for tomorrow's challenges.
Frequently Asked Questions
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Build the leaders your future depends on.
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