A longitudinal study of the efficacy of the Cellfield reading intervention in a South African context

Figures & data

Table 1. Testing procedure for the treatment and control groups.

	WRMT-R	GORT 4/5
Treatment group
Baseline (before Cellfield intervention): Conducted between 11.2014–07.2019, secondary data	Form G	Form A
Post-test (directly after Cellfield intervention): Conducted between 02.2015–08,2019, secondary data	Form H	Form B
Delayed post-test (minimum of 12 months after Cellfield intervention): Conducted between 03.2020–09.2020	Form G	Form A
Control group
Baseline: Conducted between 09.2016–07.2019, secondary data	Form G	Form A
Delayed post-test: Conducted between 03.2020–09.2020	Form H	Form B

Table 2. Descriptive statistics: Standard Scores per variable for treatment and control groups.

	Group	WI Base Std Score	WI Post Std Score	WI Delay Std Score	WA Base Std score	WA Post Std Score	WA Delay std score	PC Base std score	PC Post Std Score	PC Delay Std Score	Rate Base Std Score	Rate Post Std Score	Rate Delay Std Score	Acc Base Std Score	Acc Post Std Score	Acc Delay Std score	Comp Base Std Score	Comp Post Std Score	Comp Delay Std Score
Mean	Treatment	90.4	96.3	99.2	92.7	102	103	93.2	97.8	100.0	6.39	6.85	7.61	7.54	9.46	9.76	8.20	9.78	9.83
	Control	100	–	97.6	98.5	–	99.2	91.9	–	93.6	7.00	–	7.73	9.36	–	10.3	8.73	–	9.18
Median	Treatment	89.0	94.0	97.0	93.0	101	101	93.0	98.0	100	7.00	7.00	7.00	8.00	9.00	10.0	8.00	10.0	10.0
	Control	97.0	–	99.0	103	–	99.0	92.0	–	94.0	7.00	–	7.00	9.00	–	10.0	9.00	–	9.00
Standard deviation	Treatment	6.34	6.77	10.0	5.98	6.32	8.70	7.43	7.07	7.08	2.01	2.40	1.58	1.92	1.50	1.30	1.89	1.72	1.56
	Control	6.12	–	4.78	6.96	–	9.14	7.25	–	6.12	1.48	–	1.90	2.42	–	1.35	1.68	–	1.60
Range	Treatment	24.0	30.0	46.0	25.0	25.0	47.0	29.0	34.0	29.0	8.00	11.0	8.00	9.00	6.00	5.00	9.00	7.00	7.00
	Control	17.0	–	14.0	20.0	–	30.0	24.0	–	20.0	4.00	–	5.00	8.00	–	5.00	5.00	–	5.00
Minimum	Treatment	81.0	85.0	85.0	81.0	91.0	88.0	78.0	77.0	86.0	3.00	2.00	4.00	4.00	7.00	7.00	3.00	6.00	6.00
	Control	93.0	–	89.0	86.0	–	87.0	83.0	–	83.0	5.00	–	5.00	5.00	–	7.00	6.00	–	7.00
Maximum	Treatment	105	115	131	106	116	135	107	111	115	11.0	13.0	12.0	13.0	13.0	12.0	12.0	13.0	13.0
	Control	110	–	103	106	–	117	107	–	103	9.00	–	10.0	13.0	–	12.0	11.0	–	12.0
Shapiro-Wilk W	Treatment	0.964	0.936	0.916	0.981	0.962	0.917	0.971	0.971	0.983	0.935	0.971	0.936	0.931	0.923	0.938	0.932	0.954	0.959
	Control	0.855	.	0.904	0.836	.	0.955	0.937	.	0.974	0.875	.	0.824	0.954	.	0.808	0.945	.	0.910
Shapiro-Wilk p	Treatment	0.217	0.024	0.005	0.719	0.182	0.006	0.376	0.361	0.776	0.022	0.378	0.023	0.015	0.008	0.027	0.017	0.100	0.145
	Control	0.049	–	0.209	0.028	–	0.709	0.490	–	0.925	0.090	–	0.019	0.689	–	0.012	0.580	–	0.241

Treatment group n = 41, Control group n = 11.

Base = baseline test; Post = Post-test; Delay = Delayed post-test.

Exp = Treatment group; Control = Control group.

WI = Word Identification, WA = Word Attack, PC = Passage Comprehension, Acc = Accuracy, Comp = Comprehension.

Table 3. Chi square and pairwise comparison statistics for Word Identification (WI), Word Attack (WA), Passage Comprehension (PC), Rate, Accuracy (Acc) and Comprehension (COMP).

			Baseline – Post- test		Baseline – Delayed post- test		Post-test – Delayed post-test
n = 41	χ^2 (2)	p	Statistic	p	Statistic	p	Statistic	p
WI	39.1	<.001	7.1	<.001	7.65	<.001	0.55	0.59
WA	56.9	<.001	11.24	<.001	12.03	<.001	0.79	0.43
PC	35	<.001	6.37	<.001	6.97	<.001	0.59	0.55
Rate	20.6	<.001	3.04	.003	5.15	<.001	2.11	0.04
Acc	56.3	<.001	11.5	<.001	11.5	<.001	0	1
Comp	32.4	<.001	6.51	<.001	5.96	<.001	0.5	0.58

WI = Word Identification, WA = Word Attack, PC = Passage Comprehension, Acc = Accuracy, Comp = Comprehension.

Table 4. Effect sizes of observed improvements in WI, WA, PC, Rate, ACC and Comp.

	Baseline – Post-test			Baseline – Delayed Post-test
n = 41	Mean difference (SS)	Kendall’s W	Effect size	Mean difference (SS)	Kendall’s W	Effect size
WI	5.58	.79	Large	8.76	.48	Moderate
WA	8.95	1	Large	10.5	.86	Large
PC	4.56	.6	Large	6.71	.53	Large
Rate	.46	.22	Small	1.22	.42	Moderate
Acc	1.92	.98	Large	2.22	.78	Large
Comp	1.58	.69	Large	1.63	.39	Moderate

WI = Word Identification, WA = Word Attack, PC = Passage Comprehension, Acc = Accuracy, Comp = Comprehension.

Figure 1. Word identification group comparison.

Figure 2. Word attack group comparison.

Figure 3. Passage comprehension group comparison.

Figure 4. Rate group comparison.

Figure 5. Accuracy group comparison.

Figure 6. Comprehension group comparison.

Data availability statement

The data that support the findings of this study are openly available in figshare at DOI:10.6084/m9.figshare.23544744.