“…For example, explaining to children that they should say "I don't know" or "I don't understand" does not necessarily have a positive impact on a child's conversational behaviour (Beuscher & Roebers, 2005;Blades, Waterman, & Gibson, 2003;Ellis, Powell, Thomson, & Jones, 2003;Waterman, Blades, & Spencer, 2004). A further issue is that interviewers' implementation of the ground rules, both in England and Wales and in other countries, is often incomplete and inconsistent (Cederborg, Orbach, Sternberg, & Lamb, 2000;Hershkowitz & Elul, 1999;Powell & Hughes-Scholes, 2009;Thoresen, Lønnum, Melinder, Stridbeck, & Magnussen, 2006;Westcott & Kynan, 2006).…”