# Rachel Salvador

[**Behind the metric: how we developed “Time Spent Learning Well”**](https://blog.duolingo.com/time-spent-learning-well/)

[**How lesson transparency helps learners reach their goals**](https://blog.duolingo.com/duolingo-difficult-exercises/)

[**El impacto de la transparencia en el aprendizaje**](https://blog.duolingo.com/transparencia-en-el-aprendizaje/)

[**El impacto de la transparencia en el aprendizaje**](https://blog.duolingo.com/impacto-transparencia-en-aprendizaje/)