An increasing number of countries are moving to second-generation teacher career models, where differentiation is made between teachers on the basis of their performance rather than on their qualifications or length of service. Career structures that widen the opportunities available to teachers appear to be the most promising for teacher motivation. Yet little is known about the effects that teacher career reforms have on teachers. How do teachers perceive them? What are the effects on teacher motivation, attraction, and retention? What conditions need to be in place for career structure reforms to yield positive effects for the profession? This brief focuses on the experience of countries which have introduced those career structures, known as 'career ladders', which have a strong element of horizontal mobility (where teachers are promoted to more advanced levels even while classroom teaching remains key to their work). It sets out lessons drawn from the research into teachers' perceptions of career reforms and the broader effects of these on the profession. The research findings aim to provide policymakers and governments with a variety of options with regard to the design of teacher careers, highlighting management implications as well as perceived effects of teacher career reforms on teacher motivation, attraction, and retention. [For "Why Reform Teacher Careers and What Models Are Emerging? Teacher Career Reforms: Learning from Experience. IIEP Research Brief. No. 1," see ED621977.]