Health Education Research Advance Access originally published online on August 31, 2006
Health Education Research 2006 21(5):695-704; doi:10.1093/her/cyl082
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Krachtvoer: process evaluation of a Dutch programme for lower vocational schools to promote healthful diet
1 Department of Health Education and Health Promotion, Maastricht University, PO Box 616, 6200 MD Maastricht, the Netherlands
2 TNO-prevention, PO Box 2215, 2301 CE Leiden, the Netherlands
3 Department of Experimental Psychology, Maastricht University, PO Box 616, 6200 MD Maastricht, the Netherlands
4 Department of Public Health, Erasmus University Medical Center, PO Box 1738, 3000 DR Rotterdam, the Netherlands
*Correspondence to: J. Brug. E-mail: j.brug{at}erasmusmc.nl
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Abstract |
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The aim of this study was to examine the fidelity and completeness of the implementation of a school-based healthful diet promotion programme called ‘Krachtvoer’ (we use the Dutch title of the programme throughout this article. A possible translation is Power Food, but this does not reflect the play on words in the Dutch title), aimed at lower vocational training students aged 12–14 years. The teachers' and students' opinions of the programme were also assessed, as well as the association between these opinions and the level of implementation. Data were collected through structured teachers' monitoring reports, in-class observations and in-depth interviews with teachers. Further data were drawn from a student questionnaire included in a concurrent cluster-randomized baseline post-test experimental study evaluating the effects of the programme. The present study indicates that the teachers implemented the programme largely according to plan, that the teachers appreciated most parts of the programme and that the students who were exposed to the programme were more appreciative of their nutrition education lessons than students who followed the usual curriculum. However, programme elements that teachers did not like were often not implemented. We conclude that the Krachtvoer programme is a promising tool to encourage students in lower vocational training to adopt diets that are more healthful. The present study revealed the stronger and weaker parts of the programme and can thus guide programme improvement.
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Introduction |
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Unhealthful dietary habits are common among adolescents in the Netherlands as well as in many other countries [1–5], and have been found to be associated with increased risk of overweight, obesity, concentration problems at school and, in the long run, a higher risk of chronic diseases such as diabetes, cardiovascular diseases and certain types of cancer [6–10]. Improving the nutritional habits of adolescents is, therefore, important. Moreover, healthful eating during youth may help to establish more healthful dietary choices in later life [11–13]. Especially, when children transfer from primary school to secondary school, their eating habits change and become less healthful [14]. Intervening at this age may therefore prevent undesirable eating behaviour from becoming habitual. Further, adolescents from lower socio-economic position (SEP) groups have less favourable diets than their peers from higher SEPs [15, 16]. Interventions promoting a healthful diet should, therefore, be especially suitable for lower SEP groups.
‘Krachtvoer’ is a Dutch nutrition education programme that was specifically developed for students aged 12–14 years with low social economic status. The programme aimed to increase students' consumption of fruit and fruit juice, decrease the consumption of high-fat snacks and increase breakfast frequency and quality. The effect of the Krachtvoer programme was assessed in a cluster-randomized baseline post-test experimental design in which schools were randomly allocated to either the Krachtvoer intervention or a standard curriculum control condition [17]. This study revealed small beneficial effects on the behavioural outcome indicators related to fruit intake and most behavioural outcome indicators related to high-fat snack intake. With regard to breakfast habits, beneficial effects were only found for vitamin C and total saturated fat intake. Some positive behavioural effects occurred in the total target population, others mainly or only among students with the least desirable values at baseline.
The literature on health promotion emphasizes the importance of process evaluation. As health promotion and health education interventions become more complex, the need increases to document and analyse the processes of these interventions in order to interpret programme outcomes and failures and to guide future intervention efforts [18, 19]. The specific aim of the present process study was to investigate the completeness, fidelity and appreciation of the implementation of the programme. ‘Completeness’ indicates the proportion of programme activities and components that are actually delivered, whereas ‘fidelity’ indicates the degree to which a programme is implemented with its methods and strategies intact [19]. We also examined the opinions of the teachers and students about the programme, as well as the association between these opinions and the level of implementation.
The intervention
In the development of the programme, some key aspects of intervention mapping (IM) were used [19]. IM is a framework for effective decision making at each step in the process of developing, implementing and evaluating health education programmes. As recommended in the IM procedure, available theoretical knowledge was used and additional studies were conducted to justify many decisions that had to be made in the process of developing a behavioural change programme. These included decisions not only on general programme goals, specific learning and performance objectives and the target group but also on the theoretical intervention methods and practical strategies to develop the final intervention programme.
Performance objectives were formulated based on self-management theory [19–21] and preliminary qualitative [22] and quantitative studies [23] on personal and social environmental predictors of the target behaviour. Self-management theory describes how individuals can be motivated and enabled to self-correct habits that are not healthful. Students were expected to (i) self-assess their personal fruit, snack and breakfast intakes; (ii) compare their intakes with recommended levels; (iii) indicate reasons for observed discrepancies between their own intakes and recommendations; (iv) propose solutions, i.e. set goals to close the gap with the recommended intake levels; (v) implement those solutions and (vi) evaluate their personal goal performance.
Focus group interviews with students, parents and teachers were conducted to examine the requirements in terms of overall programme design that would promote adoption and implementation, such as the number and length of the lessons and the number of optional elements [18]. During the whole development process, a consultation team consisting of experts in the field of nutrition and the theory of education gave advice on the programme.
The programme consisted of 8 lessons of 50 min that had to be completed within a 3-month period (see Table I). A combination of materials were used: various so-called task forms, postcards and posters, a ‘survival kit’ (a lunchbox with three healthful food items, viz. a piece of fruit, a health food snack and a breakfast product and a flyer), a magazine, a video, a website, a take-home bag with a newsletter and food items for the parents, taste tests of various products and a manual to assist the teacher in giving the different lessons. Many of the materials featured three cartoon characters related to the targeted behaviour.
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The task forms guided the students through the programme. Students completed these forms individually, in small groups or as a class. There were three types of task forms. Information forms were aimed at providing relevant knowledge and were always linked to an action form or a question form. An action form encouraged students to actually do something, for example, a taste test, assessing what distinguishes a ‘real’ fruit juice from other fruit-like drinks, making their own fruit shake, tasting different breakfast cereals or writing down their own ideas for healthful recipes. A question form asked students to answer questions or to write down options or decisions, for example, reporting how many pieces of fruit they normally ate or setting and writing down personal goals for dietary change.
In Phase 1 of the programme (lessons 1–4), the first activities were aimed to raise students' enthusiasm for the programme; and the subsequent activities were linked to the first three performance objectives. In Phase 2 (lessons 4–7), all activities were aimed to help students to overcome their personal reasons for not eating a healthier diet (performance Objective 4). In this phase, teachers were allowed to vary the activities and the order in which they were carried out, but were expected to, at least, offer the action form to test nutrition knowledge, show the video that illustrated how social influences affect dietary choices, discuss the magazine and carry out one or more optional activities such as taste testing. In the third and final phase (lessons 7 and 8), the activities were linked to the last two performance objectives.
Adoption strategy
In the Netherlands, secondary education is divided in different levels: university preparatory education, senior general secondary education and preparatory secondary vocational education. Children with a lower SEP background are over-represented in preparatory secondary vocational education schools. A random sample of 80 schools were drawn from a list of addresses of 219 preparatory secondary vocational educations schools in the three southern regions of the Netherlands. Twenty-five schools agreed to participate and met the inclusion criteria. The main reasons for non-participating were time problems or not complying with the inclusion criteria. After recruitment, the schools were randomly assigned to the experimental group (13 schools) or the control group (12 schools). Before the actual start of the baseline measurements, one experimental school withdrew because of time problems. The baseline questionnaires of another experimental school were never received, even though the school claimed to have sent the completed questionnaires to the study centre. Before the start of the programme, all schools were visited and verbal information about the intervention procedure was given. During the intervention, two researchers were available for questions, comments or problems.
Eleven schools with 15 teachers, 41 classes and 1021 students implemented the intervention. Boys and girls were equally represented. In total, 35% of the students were 12 years old or younger, 51% were 13 years old and 14% were 14 years or older at the start of the programme.
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Method |
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Data were collected throughout the implementation period of the programme (September–December 2002) by means of ‘triangulation’, i.e. using multiple data sources and methods to measure the same process and effect indicators [24]. To assess completeness of implementation and the teachers' opinions of the programme, the teachers were asked to fill in structured monitoring reports. The reports included questions on teaching time, activities completed, materials used, general impressions and student reactions. The reports were structured according to the topics and lessons of the programme, and most questions were open ended to give the teachers the maximum opportunity to express their opinions. The teachers were to complete the reports after each lesson.
To assess fidelity of implementation, in-class observations were made. We aimed to observe at least 1 lesson with two observers in each experimental school. During and immediately after the lessons, each of the observers completed a structured form on the activities completed, materials used, teaching procedure, the students' reactions and participation and potential obstructing factors.
One to three months after completion of the intervention, semi-structured interviews were conducted with the participating teachers of the experimental schools to assess their opinions about the programme, their perceptions of the students' opinions as well as additional information about programme implementation. The teachers were requested to give a general impression of the programme, to state their opinions of the various programme materials and to report on the students' reactions to the programme. Further, as an indirect indicator of the teachers' opinions, we asked for their perceptions of the effect of the intervention on their students' dietary habits. Finally, additional information about the implementation was collected by questions on perceived difficulties with the implementation and perceived gaps. The interviews lasted 
30 min.
To assess the students' opinions about the programme, a section with process questions was included in the post-test questionnaire that was part of the effect evaluation study [17]. The process questions in this questionnaire consisted mainly of closed questions with five-point answering scales, and the questionnaire was completed in the classroom under teacher supervision. Students in the experimental schools as well as in the control schools who were exposed to the normal nutrition education curriculum filled in the questionnaires. The general opinion of the programme was measured by asking students in the experimental as well as the control schools to indicate how pleasant (very pleasant–very unpleasant), interesting (very interesting–very uninteresting), difficult (very easy–very difficult) and new (very new–very familiar) they found the nutrition lessons. The students were further asked if they had talked about their nutrition lessons at home. In addition, the students in the experimental schools were asked to rate the lessons on a scale from 1 to 10 and to give their opinion on the various programme materials, were asked to indicate how closely they had read the magazine and the information on the website (did not look at it–read it all) and whether they had asked their parents to buy the products that had been tasted during lessons (yes–no).
Data analyses
Based on the completed teachers' monitoring reports and observation forms, the researcher wrote overall summary reports for each topic and lesson. These summaries were checked by two other researches. The teachers' interviews were tape recorded and transcribed. Intonations and observed non-verbal behaviour were noted on the transcripts. All relevant text fragments from the transcripts were coded and categorized by the researcher according to the list of interview topics. Summary reports were written and checked by two other researchers.
Statistical analyses of the quantitative process data in the student questionnaire were conducted with SPSS version 11.0. T-tests were conducted with the study condition as the independent variable and perceived pleasantness, interestingness, difficulty and novelty as the dependent variables. Chi-square tests were conducted to evaluate the relation between conditions and talking about the lessons at home. A significance level of 0.05 was used.
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Results |
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Response
Of the 15 teachers who implemented the programme, 10 returned the monitoring reports. Five teachers failed to provide the monitoring reports, stating postal delivery problems and time investment problems as their reasons. Ten teachers in eight schools were observed. All 15 participating teachers of the experimental schools were interviewed. All students who were present during the data collecting hours completed the post-test questionnaire (n = 1021 in the experimental schools and n = 591 in control schools).
Completeness of implementation
The monitoring reports and interviews revealed that eight teachers had spent between 4 and 8 lessons lasting 100 min each, while six teachers had spent between 7 and 11 lessons lasting 50 min each, and one teacher had spent 7 lessons lasting 60 min each on the programme. All teachers spent the requested 400 min on the intervention and most teachers spent even more time on the intervention.
The findings from the monitoring reports, the in-class observations and the teachers' interviews showed that 14 of the 15 teachers had followed the phased structure of the programme. One teacher had used the programme more as a supplement to the standard curriculum. All 15 teachers had completed Phase 1. In total, 11 of the 15 teachers had offered all the prescribed elements of Phase 2, while two teachers had failed to offer one optional activity and the two remaining teachers had failed to offer the action form testing nutrition knowledge and the social influences video. All 15 teachers had discussed the magazine with their students. Optional activities frequently included testing the taste of unfamiliar foods (all teachers) and making fit shakes (10 teachers). Less favourite among the optional activities were testing the tastes of various types of fruit (five teachers) and the ‘kiwi-eating contest’ (zero teachers). Only four of the 15 teachers had completed all elements of Phase 3. Five teachers had discussed the goal-setting forms but had failed to discuss the related behaviour evaluation form. The other six teachers had not discussed any of these forms.
According to the monitoring reports and interviews, additional activities and materials were used during the intervention, for example, watching a video with general nutrition information, tasting healthful snacks other than those provided by the programme, making healthful snacks, preparing and eating lunch during school hours or other cooking exercises, using general nutrition internet sites, drawing nutrition products as a preparation for the recipe contest, making advertisements, using information on healthful diets from books that are part of the standard curriculum and visiting a greengrocer to inspect the variety of fruits on offer.
Based on the in-class observations, the students' participation was evaluated as ‘good’. The students asked many questions during the observed lessons, actively participated, worked seriously and participated in discussions on the materials and activities. However, some students, especially in classes with many students, were observed to be easily distracted, and noisy surroundings were identified as possible obstructing factors.
Fidelity to the programme
The in-class observations revealed that 7 of the lessons were executed according to the Krachtvoer curriculum. In 3 of the observed lessons, the teachers used procedures that conflicted with the programme. Some teachers used self-developed task forms, changed the order of the main phases, and one teacher used the programme as a supplement to the standard curriculum. Further, the in-class observations revealed that some of the additional activities implemented by teachers on their own initiative, such as watching a nutrition education video, using nutrition information internet sites and using information on healthful diets from books that are part of the standard curriculum, interfered with the phase structure or behavioural focus of the programme.
General opinions of the programme
Both the teachers' monitoring reports and the interviews indicated that most teachers had favourable opinions of the programme. They praised the programme for its practical approach, the design of the materials, the fact that the programme was provided free of charge and the diversity of strategies and activities. Taste testing unfamiliar foods, the recipe contest, the social influence video and the fruit-shake preparation were frequently mentioned as the most highly appreciated activities. Some of the teachers added that lower vocational students, because they are easily distracted, must be actively encouraged to work with the materials. All teachers expressed the opinion that the materials were appropriately tailored to the students' general educational level. Some teachers said that they would have preferred the inclusion of a more general introduction to the topics, information on the recommended daily intake, label reading and food hygiene in the programme. These topics are part of the existing curriculum. Some teachers also commented that the Krachtvoer lessons took more time than the standard curriculum and that it was difficult to estimate the duration of some activities. Some would like to see examination papers included. Ten teachers indicated that they thought that the students had become more aware of their own dietary behaviour as a result of the programme. Three teachers, however, expressed their doubts as to whether the students would really adopt healthful dietary changes in their regular diets. Both the teachers' monitoring reports and the interviews indicated that some teachers intended to continue using the programme.
The student questionnaires showed that the students were moderately positive about the programme. The students in the Krachtvoer schools perceived their nutritional lessons as significantly more pleasant, more interesting, easier and newer than those in the control schools (Table II).
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Opinion on programme materials
Based on the monitoring reports, in-class observations and teacher interviews, the survival kit was the most successful of the materials of Phase 1 and was perceived as making the students enthusiastic and curious about the programme. The posters seemed to support the intervention. The teachers were less positive about the information and question forms of Phase 1. Teachers experienced these forms as boring and poorly structured, mainly because of the number of forms. Most teachers reported that the task forms were well structured.
Favourite activities in Phase 2 were taste testing unfamiliar foods, making a fruit shake, reading the magazine, taking part in the recipe contest and taking home the bag with a newsletter and the food items for the parents. The main reason was the practical approach and the many different strategies used in the activities. Because the students could really taste, feel and smell the products, they were very motivated to participate in the taste testing and fruit-shake lessons. In some cases, however, not enough facilities and equipments were available, and a great deal of organization skill was needed to do the taste testing with unfamiliar foods and making a fruit shake in the classroom. It was further perceived to be important that the products for the taste testing should not be close to their expiration dates, and that different brands of products should be provided.
Most teachers reported that the question form used to formulate specific and achievable goals in Phase 3 was difficult to use. Some students were not willing or able to set feasible goals. Some teachers said that students felt that setting goals for behaviour change interfered too much with their personal freedom, most likely because they did not like the ‘boring’ goal-setting activity. Some teachers noted that they appreciated the conversations about goal setting and that the students had formulated valuable intentions. Our in-class observations revealed that some teachers integrated Phase 3 with activities belonging to Phases 1 and 2.
The students of the Krachtvoer schools rated the various programme materials as positive (Table III). The recipe contest and the video illustrating social influences were appreciated most. Further, the task forms, magazine and website were perceived as easy to use and clear. The students evaluated the programme with a mark of 7.2 on a scale of 1–10. In total, 88% of the students had read the magazine and 47% of the students had read the information on the website. In total, 54% of the students reported to have asked their parents to buy products that were taste tested during the lessons. Students in the Krachtvoer schools were more likely to talk about the nutrition lessons at home (60%) than the control students (20%) (
2(1) = 213.20, P = 0.000).
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Discussion |
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TopAbstractIntroductionMethodResultsDiscussionConflict of interest statementReferences |
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The findings of the present study indicate that the teachers implemented the Krachtvoer programme largely according to plan, that the teachers appreciated most parts of the programme and that the students who were exposed to the programme were more appreciative, i.e. perceived their nutritional lessons as significantly more pleasant, more interesting, easier and newer than students who followed the usual curriculum.
Although the teachers added extra activities and materials to the programme, the degree of completeness of the programme's implementation was quite good. In most cases, the order and content of lessons were in accordance with the phased structure of the programme. However, better guidance for the teachers might have resulted in even better implementation. The process evaluation especially indicated non-optimal implementation of Phase 3 by both teachers and students.
The results indicate that the fidelity of the implementation of the programme was good, but some teachers used procedures and activities in their nutrition education lessons that conflicted with the programme. During the intervention, we tried to avoid this by providing a clear description of the main aim and the specific sub-aims of the programme and its lessons in the teacher's manual. Perhaps, a more intensive training programme for the teachers might have resulted in greater intervention fidelity.
Although completeness and fidelity of the implementation were quite good, they were definitely sub-optimal and, in all likelihood, this resulted in sub-optimal impact of the intervention. Especially, Phase 3 was designed to translate positive intentions into actions. And its sub-optimal implementation may have prevented greater behaviour changes.
We found the degree of implementation to be influenced by the students' preferences. Teachers were less enthusiastic about those lessons, which their students reported not to have enjoyed. Some teachers did not even implement lessons that they did not expect their students to appreciate. For example, in Phase 3, the students felt that setting goals for behavioural change interfered too much with their personal freedom, and this made the teachers hesitant to implement this part of the programme. These findings support those of a preliminary study where teachers perceived students' preferences as important factors in their decision to adopt specific classroom-based education [25]. Developing alternatives for those activities that students do not appreciate can improve the programme's implementation and efficacy.
The positive opinions about the programme among the teachers were also reflected by the fact that some of the teachers reported their intention to use the programme again in the future. Of course, such a positive intention on the part of the teachers is no guarantee of actual adoption or continuation [26, 27], and teachers should be actively encouraged and supported to keep using the programme in their nutrition education classes.
In interpreting the findings, some methodological issues need to be taken into account. The teachers who participated in the present study might have been a select group as they all indicated to be interested in the topic of nutrition and to follow a healthful diet themselves. The results could be less positive in other study populations. Furthermore, the study may have been influenced by the Hawthorne effect—we observed lessons in the Krachtvoer schools but not in the control schools. We did, however, ask the control schools to monitor their lessons as well.
By collecting data from multiple sources and using multiple methods, we believe that we were able to carefully evaluate the implementation of the programme and the teachers/and students/opinions about the programme. Even though the individual methods had their limitations, such as the limited number of observations and incomplete monitoring, we were able to identify successful and less successful elements of the programme.
We conclude that the present study, combined with the results of the effect evaluation, shows that the Krachtvoer programme is a promising tool to encourage students in lower vocational training to adopt diets that are more healthful. The present study revealed the stronger and weaker parts of the programme and can, therefore, guide the revisions to further improve the programme. Furthermore, the study identified sub-optimal implementation of the programme that could undermine the impact of the intervention. This highlights the importance of process evaluations when implementing school interventions.
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Conflict of interest statement |
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None declared.
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References |
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Received on April 29, 2005; accepted on July 6, 2006
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