Study setting {9}
The intervention and data collection will take place in primary schools. Details of participating schools will be posted to the study registry at ISRCTN: 40249947
Eligibility criteria {10}
School inclusion/exclusion criteria
Participation is open to primary schools in London and Leeds regions, for children in Reception, Year 1 and Year 2 (age range 4-7 years). Schools decide which of these year groups will participate in the study. Special needs schools, independent schools and very small schools (less than one class group per year group) will not be included.
Individual inclusion criteria
All children in experimental group classes will receive the intervention, delivered as part of regular school teaching. Children in the control group will receive normal teaching with no intervention. No particular level of spoken English is required. However, only children with opt-in caregiver consent will contribute data to the study.
Who will take informed consent? {26a}
There will be two routes for caregiver consent for participating children. An online route will direct caregivers to a dedicated page at onlinesurveys.ac.uk, where they will receive information about the study, and can give consent for their child’s participation. However, pilots showed that many caregivers do not engage in the online route, so there will also be an in-person, on-paper consent route run by teachers in participating classes.
Additional consent provisions for collection and use of participant data and biological specimens {26b}
Caregivers can opt-in to allow the use of their child's video data for communications about the intervention and the study. Their child can participate regardless of this consent being giving.
Interventions
Explanation for the choice of comparators {6b}
The comparator condition is normal teaching with no intervention. Though there might be advantages to an active intervention comparator, the burden on schools would be increased, making recruitment difficult. The real-world comparator is likely to be schools deciding whether to alter their normal teaching to include the intervention, so this comparator should provide a good reflection of real-world decision making context.
Intervention description {11a}
Flavour School is a programme of sensory food education, aimed at primary school children aged 4-7 years. Children participate in sensory activities with food (mostly FV), to learn about how their various senses contribute to their eating experiences, whilst familiarising and ‘making friends’ with healthy foods. Children also learn conversation skills and vocabulary to describe and share their sensory experiences. The programme is delivered once-weekly over one school term. Prior to the intervention, participating teachers attend a teacher training session and are provided with teaching materials. Flavour School aims to 'grow children's curiosity and confidence in exploring foods and flavours, to support the development of healthy, happy relationships with food'. The Flavour School programme is produced and supported by the charity Flavour School (#1178084).
Criteria for discontinuing or modifying allocated interventions {11b}
None .
Strategies to improve adherence to interventions {11c}
Researchers will keep in contact with participating schools and teachers throughout the trial, to ensure intervention delivery is progressing as planned, and offer support where needed.
Relevant concomitant care permitted or prohibited during the trial {11d}
None
Provisions for post-trial care {30}
None.
Outcomes {12}
The observational scenario is a tasting activity done in small groups (see {18a}). The test activity will conducted <6 weeks before (baseline) and <6 weeks after intervention delivery is completed. Analysis metric for all measures is follow-up scores, adjusted for baseline, for all children.
Primary Measures
‘Curiosity and confidence’ are operationalised in terms of the following observable proxy behaviours.
- willingness to taste novel and familiar vegetables, legumes and fruit (supervised self-report)
- non-verbal ‘Enjoyment and Engagement’ (from observation of children’s facial expressions)
- verbal engagement (child’s speaking time and sensory vocabulary during the activity)
- normalised linear combination (mean) of 1,2&3 as an overall measure of 'curiosity and confidence' in tasting.
Validation of Noldus FaceReader
- In our experimental context, is the Noldus FaceReader software sufficiently accurate to partially replace human observers?
Exploratory analysis
- Liking for the offered range of foods (self-report)
Primary Measures
Children are not experimentally observed during the delivery of the intervention. All evaluation data are collected during the baseline and follow-up evaluation sessions, administered and supervised by the experimenter, before and after the intervention. See Appendix 2 for more details of the coding regime for annotation of the video data.
Willingness-to-taste (WTT)
Children are offered nine plant foods (see Appendix 1 for list of foods), in a compartmentalised tray. ‘Self-reported WTT’ is simply the proportion of these that a child tastes, as indicated by the faces they draw on their My Tasting Card (see Figure 2).
Children are instructed that nibbling and licking are included as tasting. A child who eats all of every sample therefore has the same self-reported WTT score as a child who takes tiny nibbles of all samples, though their behaviours are notably different. To finesse WTT scores such that these differences are noted, the human observers coding the video footage will also produce a ‘Gusto’ rating to summarise how enthusiastically each child tastes/eats the food samples, rating from 1 (very unenthusiastic) to 5 (very enthusiastic). These Gusto ratings will be used to weight the self-reported WTT scores (i.e. WTT = self-report WTT * Gusto). We will report both self-report WTT and WTT.
Enjoyment and engagement - Facial expression analysis
Individual video footage of a given child participating in the Flavour Explorers activity will be annotated continuously with an assessment of current facial expression. Coders assign an affect valence measure to the current facial expression, from -2 (very negative) to +2 (very positive), where 0 is neutral, updated upon changes of valence, such that a given Valence measure is a time series covering the duration of that child’s Flavour Explorers session-time. See Appendix 2 for more details on the coding regime. This valence time series is used to derive two measurements of behaviour which we term Enjoyment and Engagement, as defined below.
Enjoyment: a quantitative measure of child's facial expression Valence on average over one ‘Flavour Explorers’ data collection session. Calculated as mean Valence over all timesteps.
Engagement: a quantitative measure of amount of change in facial expression valence. To calculate this measure, we take the first derivative of Valence, and calculate its mean absolute value over the number of timesteps in the video recording.
Why use these two measures?
Engaging in the tasting activity can produce strong negative-valence facial expressions, for example nervousness/fear on approaching an unfamiliar food, or when tasting sour or disliked foods. A child who mostly maintains a neutral face throughout could have a similar Enjoyment (mean valence) score as a child who swings between episodes of strongly positive and negative expressions, such that positive and negative events cancel out. However, their facial behaviour is quite different. The difference is captured by the Engagement measure (which would be low for the former child and high for the latter).
Overall Measure for Non-verbal enjoyment/engagement (facial expression): Enjoyment and Engagement will be added to give a single primary measure for non-verbal enjoyment/engagement.
Verbal engagement
Each time step of the video footage is annotated using one of 2 categories/levels of verbal behaviour: 0==not talking; 1==talking. These scores will then be summed across time steps, and divided by number of timesteps, to give one number describing the proportion of speaking time across the session. See Appendix 2 for more details of the video coding scheme.
Sensory vocabulary
Coders will note (with a key press) each relevant sensory word uttered by the child being observed on video. The Sensory Vocabulary measure is then total number of relevant sensory words across one 'Flavour Explorers' session, normalised by session length.
Exploratory Analysis
Liking for the food samples (this is an exploratory analysis)
During the Flavour Explorers tasting activity, the children draw 'emoji style' faces to indicate their liking for the food samples they taste (see {18a} for more details). The primary purposes of this are (a) to serve as supervised self-report of willingness-to-taste, and (b) to give the data collection scenario the feel of an 'activity', rather than the feel of a 'test'.
The children have quite a lot of freedom in the faces they draw, and some children (especially the younger ones) are still mastering use of a pen. In pilots, the faces children drew were not always decipherable. As a result, the Liking measure is likely to be rather noisy, with limited coverage, especially for children in Reception class (i.e. the youngest children). There is no particular reason to anticipate significant pre-post changes in liking. Nonetheless, given we will have some data on children's liking for the samples, it makes sense to explore this data, noisy as it may be. For these reasons, we will examine Liking as a secondary measure, and an exploratory analysis.
Liking will be calculated as the sum of all the faces drawn on a child's My Tasting Card, where each face type is rated as follows:
'frowny' face == 0
'flat' face == 1
'smiley' face == 2
Liking will use the same statistical analysis used for the primary measures (see {20a},{20b}). We will also calculate correlation between Liking and WTT, as we are interested in the extent to which WTT depends on like/dislike for the foods offered.
Validation of Noldus FaceReader vs. Human coders
Our question here is whether related studies in the future could safely use the Noldus FaceReader to partially replace the human coders in assessing children's Enjoyment and Engagement in the Flavour Explorers tasting activity (or a similar activity). The FaceReader software has been validated against various benchmarks e.g. [47, 48] and used to assess children's expressions during activities (e.g. [49]), but our context offers some particular challenges. Our participants engage in a non-screen-based activity, so gaze direction is quite variable. Also, less training data is available for children, than for adults. In our context we are only interested in how well the automated assessment of pre-post differences in ‘Enjoyment’ and ‘Engagement’ matches those of human observers, not the moment by moment analysis of the videos.
Validation questions
- What is the mean difference, and the variability, between FaceReader and the human coders for follow-up measures of Enjoyment and Engagement, adjusted for baseline?
- How significant are these differences given effect sizes?
Independent measures
Control/Intervention group
Date of birth of child
Sex of child
Pupil Premium eligibility of child
School
School class
Participant timeline {13}
The trial runs over the 2021-22 school year. Schools nominate eligible year groups for participation. Cluster randomisation will be at the level of paired teaching class groups, within-school. For example, a school chooses Year 1 to participate. Year 1 contains two classes, 1A and 1B. At random, Class 1A is assigned to the control group, and 1B to the experimental group. See Figure 1. Schools can choose the timing of intervention delivery separately for each pair of classes. Therefore, different class pairs can have different intervention timings.
Teachers will be instructed to ensure Flavour School delivery respects class delineations, to minimise contagion. The control group receives no intervention (i.e. the standard curriculum). Pre- and post- intervention data collection is conducted for both the experimental and control groups. The control group can receive the intervention after post-intervention data collection is complete, at the school’s discretion.
Sample size {14}
There is no perfectly comparable study upon which to base our sample size estimates, as our behavioural measures and study design are novel to the domain. Using a similar testing method in a younger age group (1-3 year olds), Dazeley and Houston-Price[31] reported that out of 4 foods (2 fruits, 2 vegetables) offered to nursery school children, the mean number of foods tried was 1.44 with a standard deviation of 1.38. To measure mean increases of 0.5 (the equivalent of 50% of children eating one more food), using the same standard deviation found by Dazeley and Houston Price, a sample size of 160 children is needed in each arm (control and intervention) to provide 90% power. We will aim to recruit 400+ children, but recruitment may be challenging due to ongoing pandemic Covid19 conditions.
Recruitment {15}
Schools will be recruited by open invitation via social media, word-of-mouth, and through local authority school-facing teams and programmes. Schools will benefit from free teacher training, and reimbursement of the financial cost of the produce used for the intervention. We appreciate that this process will likely over-sample schools with an interest in food and food education. By definition, this group is the most likely to implement food education interventions, and so study results should be broadly applicable to schools choosing to introduce sensory food education. However, results of the study may not be so broadly applicable to schools mandated to introduce sensory food education.
Assignment of interventions: allocation
Sequence generation {16a}
Sequence generation will be video recorded instantaneous randomisation (die roll).
Concealment mechanism {16b}
None, as we will use instantaneous randomisation.
Implementation {16c}
The lead researcher will enrol participants. The PI will generate the random sequence, and assign clusters to the experimental/control groups on the basis of randomisation.
Assignment of interventions: Blinding
Who will be blinded {17a}
Data analysts/video coders will be blind to condition (Control/Intervention) and time point (Pre- or post-intervention) of a given video and participant under analysis. Due to the experiential nature of the intervention, it is not possible to blind the study participants (children and teachers) to their condition (control/intervention). The lead researcher, who will conduct data collection, will be pragmatically blinded to which classes/clusters are in which condition. However, this blinding is imperfect due to contact between the lead researcher and participants during data collection (e.g. a child might talk about doing Flavour School activities, revealing that their class is in the intervention group).
Procedure for unblinding if needed {17b}
N/A .
Data collection and management
Survey data will be collected from parents and teachers. A Teacher Survey (see Appendix 3) will estimate teacher engagement and process adherence. The online Caregiver Consent form also contains an optional survey asking parents about their child's eating behaviours, using a subset of the Child's Eating Behaviour Questionnaire.
Plans for assessment and collection of outcomes {18a}
Behavioural data collection is conducted through a tasting activity we call 'Flavour Explorers'. The activity itself is individual, but is performed in a peer-group of three or four to enable conversation and make the scenario comfortable for the children participating. The children are supervised by the researcher(s). The children sit on cushions on the floor, around a small circular table.
Each child is provided a small tray with nine compartments, each containing one food sample. Each compartment/food sample is marked with a different colour dot sticker. Each child is also provided a 'My Tasting Card', with nine colour blobs matching the food samples/compartments. When a child tries a food, they use 'emoji' style drawings to note their liking for the food (sad face, neutral face, or happy face) on their Card. See Figure 2. Children are given as much time as they need (within reason), and sessions typically last between 8-12 minutes.
The sample consist of seven vegetables (including a legume and a herb), and two fruits, and include both common/familiar and obscure/unfamiliar produce. Different food sample sets will be used for pre- and post-intervention testing, counterbalanced at random by school class group. See Appendix 1 for more details.
Flavour Explorers sessions will be video recorded, with an individual video stream for each child. A dedicated Yi4k+ action camera for each child is located in the centre of the table. The My Tasting Cards provide the raw data for analysis of willingness-to-taste (WTT) and liking, whilst video/audio provides raw data for affect from facial expression, and verbal engagement.
Plans to promote participant retention and complete follow-up {18b}
Participants who leave the school/class during the trial will not be included in the trial. The intervention is enjoyable, and is integrated into school-time teaching. No follow up measures are currently planned, due to shortening of the trial to accommodate Covid19-related time pressures.
Data management {19}
Please see the OASES dynamic Data Management Plan at ISRCTN: 40249947, for up-to-date data management information.
Confidentiality {27}
All video data collected will be stored securely on-site at the school where it is collected, on a dedicated external hard drive, and will remain property of the school until released to the University of Leeds for use in the study. Video data will only be released to the University of Leeds after opt-in caregiver consent is obtained for a given child. The child’s video data will then be copied to another external hard drive, which will be stored securely at the University of Leeds, School of Food Science and Nutrition. Anonymous participant ID numbers will replace names in labelling participant profiles/data. All data will be stored securely, under physical locking or password protection, on secure University of Leeds servers.
Plans for collection, laboratory evaluation and storage of biological specimens for genetic or molecular analysis in this trial/future use {33}
None.
Statistical methods
Statistical methods for primary and secondary outcomes {20a}
For each participant, pre/post-intervention difference will be calculated for each primary measure, plus the normalised sum of primary measures (to represent overall 'curiosity and confidence'). Each set of data will be analysed using regression models with pre-post difference as the outcome. Secondary measures will be examined using the same methods as primary measures. The number of clusters is too small to analyse using a multi-level model, however school and class will be included as a covariate.
For each participant, data will be collected at baseline and follow up. The main outcomes (dependent variables) will be individual scores in WTT, Enjoyment/Engagement (from facial expression), and Verbal Engagement at follow up. The difference in scores between the intervention and the control group will be calculated for each of the primary measures, plus an overall score consisting of the sum of primary measures which represents overall curiosity and confidence. Each set of data will be analysed using two level regression models (where appropriate), to take into account the clustering of children within schools. The analysis will be adjusted for baseline scores.
The intervention should benefit those children most in need of support. To reflect this in our analysis, we will split the participants into three sub-groups according to their score on a given measure at baseline (Low, Mid, High). Each grouping will cover 1/3 of the range for that measure. It is important that any benefits be observed in the Low and/or Mid groups, and not just be driven primarily by the High group. High scores are considered desirable in all measures.
The Liking secondary measure will be examined using the same regression methods.
Interim analyses {21b}
None. The risks of harm from the current trial and intervention are low, and no greater than those for normal school teaching activities.
Methods for additional analyses (e.g. subgroup analyses) {20b}
At the individual level, we will control for any effects of sex, age, and Pupil Premium[2] eligibility. At the group level, we will control for any effects of school and school class group. Any group differences will be interpreted in the light of information about process adherence and teacher engagement, as reflected in the teacher survey (see Appendix 3).
Methods in analysis to handle protocol non-adherence and any statistical methods to handle missing data {20c}
Analysis will follow intention-to-treat principles for all participants who complete the intervention. Adherence will be assessed via a teacher survey, and supported via personal contact with participating teachers and school visits by researchers to observe delivery of the intervention and offer support/guidance where necessary. A participant’s data will be excluded if it is not possible to gather post-intervention data.
Plans to give access to the full protocol, participant level-data and statistical code {31c}
Open access to full protocol and code is anticipated. Children’s video data will be kept private by default. Anonymised measures and statistical data will be open access via University of Leeds Library Data Service.
Oversight and monitoring
Composition of the coordinating centre and trial steering committee {5d}
The co-ordinating centre is the School of Food Science and Nutrition, at the University of Leeds. The lead researcher is conducting data collection and the day-to-day running of the trial. The PI, together with a project mentor, are overseeing and supporting the lead researcher.
Composition of the data monitoring committee, its role and reporting structure {21a}
This is a small trial of a food education programme. Both scale and risk are small enough that a dedicated data monitoring committee has not been judged proportionate. The lead researcher will be the primary data handler, overseen by the PI. The trial is funded by an EU H2020 grant.
Adverse event reporting and harms {22}
Adverse events/incidents in schools will be logged through the school’s standard reporting procedures, and the study team informed to log incidents in the study risk assessment and health and safety documentation. It is not anticipated that adverse incident(s) will result in discontinuation of the study. It is possible that the trial will be discontinued or postponed due to potential disruption to schools arising from the coronavirus pandemic.
Frequency and plans for auditing trial conduct {23}
There are no plans for auditing of trial conduct, due to the small size and low risks of the trial.
Plans for communicating important protocol amendments to relevant parties (e.g. trial participants, ethical committees) {25}
Changes to the protocol will be submitted to the supervising ethical committee as an amendment. Participating schools and teachers will be informed directly by email. Any changes will be submitted to Trials journal as updated versions of the protocol, and to ISRCTN as updates of the OASES study account.
Dissemination plans {31a}
Results will be reported in scientific journals. Results will be communicated directly to participating schools. Results will be publicised via conference communications, social media and health and education networks.
Footnote:
[2] The Pupil Premium is a grant to schools, providing extra funding for (means-tested) disadvantaged pupils.