How can we know if it is effective?

I have spent the last 10 years of my life in training missionaries. Training events have taken me to more than a dozen countries. Through online courses, workers from at least twice that number have participated in training that I have led. Furthermore, I head up our organization’s training department and so have the privilege of leading a great team of trainers and facilitators. But despite my experience and travels, the question does not go away. How can we know if our training is effective?

Recently I saw that the parable of the sower sheds some light on this question.

The seed falling on rocky ground refers to someone who hears the word and at once receives it with joy. But since they have no root, they last only a short time. When trouble or persecution comes because of the word, they quickly fall away. – Matthew 13:20–21

Biblical understanding

Jesus’s explanation of the seed falling on the stony ground shows us that a joyful response to the hearing of truth is no indication that people have understood the Word. As is clear from Matt. 13:15, a biblical sense of understanding is to understand with the heart, resulting in a change of behavior. We can only say that there is true understanding when the person repents and turns from their previous behavior to adopt new behaviors or habits.