The concept of early 19th Century working class education needs to be viewed cautiously.

The concept of value chain management capability needs further development and more extensive research is required.

Now however the concept of a "state of matter" needs to be more general.

As the century turns, the concept of childhood needs re-evaluation.

However, the concept of group cohesion needs to be considered.

So the whole concept of single parenthood may need rethinking.

However, some others believe that the concept needs further research.

This concept needs to be explicitly taught along with content instruction.

The concept needed to be tested on a larger scale, and I did so.

So the concept needs work, perhaps, but it seems to hold bright promise.