Something for everybody? Assessing the suitability of AAC systems for children using stated preference methods

Figures & data

Figure 1. Schematic representation of the relationship between the current study and the wider I-ASC project.

Table 1. Attributes and levels for discrete choice experiment and likert scale survey.

Attribute	Levels
Children
Receptive and expressive language	Delayed/ Receptive language exceeding expressive language
Communication ability with AAC	No previous AAC experience/ Able to use AAC for a few communicative functions/ Able to use AAC for a range of communicative functions
Child’s determination and persistence	Does not appear motivated to communicate through any methods and means/ Motivated to communicate through symbol communication systems/ Only motivated to communicate through methods other than symbol communication
Predicted future skills and abilities	Regression/ Plateau/ Progression
AAC systems
Vocabulary sets	No vocabulary set^a/ Fixed vocabulary set/ Vocabulary set with staged progression/
Size of vocabulary	Up to 50 vocabulary items^a/50–1000 vocabulary items/ More than 1000 vocabulary items
Consistency of layout	Consistency of some aspects of layout^a/ Consistency of all aspects of layout/ Idiosyncratic layout
Type of vocabulary organization	Visual scene^a/ Taxonomic/ Semantic-syntactic/ Pragmatic
Graphic representation	Photos^a/ Pictographic symbol set/ Ideographic symbol system (with rules or encoding)/ Text

^aIndicates baseline level.

Table 2. Participant demographics (N = 172).

Characteristic	Completed DCE		Did not complete DCE
	(n = 155)	%	(n = 17)	%
Age^a	40.2	10.9	46.1	10.9
Years of experience^a	11.4	9.15	11.6	9.87
Female	140	90.3	15	88.2
White ethnicity	137	88.4	12	70.6
Professional background
Speech and language therapist	117	75.5	8	47.1
Occupational therapist	11	7.1	5	29.4
Assistive technology specialist	5	3.23	0	0
Teacher	11	7.1	3	17.6
Other	12	7.74	0	0
Common diagnoses
Autism spectrum	101	65.2	12	70.6
Physical	128	82.6	12	70.6
Dyspraxia	12	7.74	2	11.8
Intellectual disability/delay	107	69	11	64.7
Neurological	39	25.2	6	35.3
Speech/language disorder	19	12.3	3	17.6
Syndromes	56	36.1	5	29.4
Location
North West England	20	12.9	2	11.8
North East England	5	3.23	1	5.88
Yorkshire and Humber	22	14.2	1	5.88
West Midlands	12	7.74	1	5.88
East Midlands	11	7.1	1	5.88
East of England	14	9.03	3	17.6
South West England	8	5.16	0	0
East England	32	20.6	3	17.6
London	18	11.6	4	23.5
Northern Ireland	5	3.23	0	0
North Wales	3	1.94	0	0
Wales	5	3.23	0	0
Mid-Wales	3	1.94	0	0
Southern Scotland	7	4.52	0	0
Central Scotland	11	7.1	1	5.88
Northern Scotland	6	3.87	0	0
Non-UK	4	2.58	0	0

DCE: discrete choice experiment.

^aMean and standard deviation.

Figure 2. Screenshot of example discrete choice experiment task.

Table 3. For each child vignette, the proportions of systems rated at least 5 and at least 6.

Language	AAC experience	Motivation	Trajectory	Percentage of systems rated over
				5	6
Delayed	No experience	Motivated (non-AAC)	Regress	51.1	0
R > E	No experience	Motivated (non-AAC)	Regress	53.6	0
Delayed	No experience	Not motivated	Regress	70.8	0
Delayed	No experience	Motivated (non-AAC)	Plateau	71.2	0
Delayed	Few functions	Not motivated	Regress	71.9	0
R > E	No experience	Not motivated	Regress	73	0
Delayed	No experience	Motivated (non-AAC)	Progress	73.7	0
R > E	No experience	Motivated (non-AAC)	Plateau	73.7	0
R > E	No experience	Motivated (non-AAC)	Progress	75.2	0
R > E	Few functions	Not motivated	Regress	75.5	0
Delayed	No experience	Not motivated	Plateau	82.5	0
Delayed	Few functions	Not motivated	Plateau	83.6	0
Delayed	No experience	Not motivated	Progress	86.1	0
R > E	No experience	Not motivated	Plateau	86.1	0
Delayed	Few functions	Not motivated	Progress	87.6	0
R > E	Few functions	Not motivated	Plateau	88	0
R > E	Few functions	Not motivated	Progress	88.7	0
R > E	Few functions	Motivated (AAC)	Regress	93.4	0
R > E	No experience	Motivated (AAC)	Regress	94.2	0
Delayed	No experience	Motivated (AAC)	Regress	95.6	0
Delayed	Few functions	Motivated (AAC)	Regress	95.6	0
Delayed	Many functions	Motivated (AAC)	Regress	95.6	0
Delayed	No experience	Motivated (AAC)	Plateau	98.5	0
Delayed	Few functions	Motivated (AAC)	Plateau	98.5	0
R > E	No experience	Not motivated	Progress	86.5	0.365
R > E	Few functions	Motivated (AAC)	Plateau	97.1	2.19
R > E	No experience	Motivated (AAC)	Plateau	97.1	3.28
Delayed	Many functions	Motivated (AAC)	Plateau	98.5	3.28
R > E	Many functions	Motivated (AAC)	Regress	93.4	4.38
Delayed	Few functions	Motivated (AAC)	Progress	95.6	8.76
Delayed	No experience	Motivated (AAC)	Progress	96.7	9.12
R > E	Many functions	Motivated (AAC)	Plateau	97.1	12
R > E	Few functions	Motivated (AAC)	Progress	94.5	12.8
R > E	No experience	Motivated (AAC)	Progress	94.5	13.1
Delayed	Many functions	Motivated (AAC)	Progress	96.7	15
R > E	Many functions	Motivated (AAC)	Progress	95.6	20.4

R > E = Receptive language exceeding descriptive language.

Figure 3. Ratings of the most suitable AAC system for each child vignette.

Figure 4. Number of times each AAC system level was part of a child vignette’s most preferred system.

Figure 5. The I-ASC explanatory model of decision making. From Murray et al. (2019).

Murray, J., Lynch, Y., Meredith, S., Moulam, L., Goldbart, J., Smith, M., Randall, N., & Judge, S. (2019). Professionals’ decision-making in recommending communication aids in the UK: Competing considerations. Augmentative and Alternative Communication, 35(3), 167–179. https://doi.org/10.1080/07434618.2019.1597384

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