While there isn't a universally accepted set of "four traits" for constructive criticism, here are four key elements that make it effective and helpful:

1. Specific and Concrete: Constructive criticism focuses on specific behaviors or actions, rather than vague generalizations. It uses clear examples to illustrate the points being made.

2. Descriptive, Not Judgemental: It avoids using accusatory or blaming language. Instead, it focuses on the impact of the actions or behaviors, using "I" statements to express how the person's actions make the receiver feel.

3. Solution-Oriented: Constructive criticism doesn't just point out problems; it offers actionable suggestions for improvement. It focuses on what can be done differently in the future.

4. Respectful and Empathetic: The tone is positive and encouraging, even when addressing challenging issues. It acknowledges the person's effort and potential, fostering a sense of collaboration and mutual understanding.

It's important to note that constructive criticism is a two-way street. It requires both the receiver and the giver to be open to feedback and willing to learn from it.