Possible Clues:

• Conclude Panama, say, is not productive
• Assume tradesman finishing early is not productive
• Conclude letter on Scrabble board will be unproductive
• Gather English literature must be rejected as barren
• Conclude part of Scrabble game with 'barren'
• Conclude a wall covering is sterile
• Assume one involved in Scrabble is not productive
• Deduce that one component of Scrabble is not productive
• Presume oriental settled back to be unproductive
• It's not productive to make a deduction on old-fashioned hat