. Author manuscript; available in PMC: 2011 Jul 27.

Published in final edited form as: Except Child. 2010 WINTER;76(2):135–165. doi: 10.1177/001440291007600201

TABLE 2.

Research Program Study Conditions and Findings

Study	Conditions and Findings
Study 1	(1) NCs: drill and practice
	(2) Procedural calculations: regrouping concepts, algorithms, estimation
	(3) NCs plus procedural calculations
	(4) Control (word identification)
	Across MD and MDRD: on NCs, (1) = (3) > (2) = (4); no evidence of transfer

Study 2	(1) NCs: drill and practice
	(2) NCs: conceptual/decomposition strategies
	(3) Procedural calculations: regrouping concepts, algorithms, estimation
	(4) Control (no tutoring)
	For MD: on NCs, (1) = (2) > (3) = (4); no evidence of transfer
	For MDRD: on NCs, no differences

Study 3	(1) NCs: counting strategies plus drill and practice
	(2) NCs: counting strategies embedded within word-problem remediation
	(3) Control (no tutoring)
	Across MD and MDRD: on NCs, (1) = (2) > (3); evidence of transfer to procedural calculations; on word problems, (3) > (1) = (2)

Study 4	(1) NCs: counting strategies with brief but deliberate practice, embedded within word-problem remediation
	(2) NCs: counting strategies without deliberate practice, embedded within word-problem remediation
	(3) Control (no tutoring) Across MD and MDRD: on NCs, (1) > (2) > (3); evidence of transfer to procedural calculations; on word problems, (3) > (1) = (2)

Note. NCs = number combinations; MD = mathematics difficulty; MDRD = mathematics difficulty plus reading difficulty.