The use of secondary school student ratings of their teacher’s skillfulness for low-stake assessment and high-stake evaluation

Previous studies in higher education have shown that the reliability of student ratings of teaching skill increases if multiple ratings by different students are aggregated. This study examines the generalizability of these findings to the context of secondary education. Also, it seeks to validate these findings by comparing reliability levels estimated by the routinely used nested design with those estimated using a more complex design. The sample consisted of 410 students from 17 classes rating 63 teachers working at eight schools across the Netherlands. Using the nested design, the study replicates findings of previous studies in higher education. The findings illustrate how the reliability level of secondary school students’ ratings increases with an increasing number of students. However, these replicated reliability levels were not validated by the more complex design which provided lower estimates. This indicates that the nested design may not provide accurate estimations of rating reliability

Role of product characteristics for the adoption of fruit and fruit product innovations

The aim of this study was the identification of those product characteristics that are important for the adoption of fruit and fruit product innovations by consumers. Sixteen focus group discussions were held in four European countries (Greece, The Netherlands, Poland, and Spain). Different aspects of six innovative fruit products were discussed, revealing those characteristics that were important for the adoption of each of them. It was observed that the participants did not perceive fruit innovations as a homogenous group, but assigned them to different groups, which led to a number of categories of fruit innovation. Three categories concerned the level of preparation of fruit. These were fresh, prepared, and processed fruit product innovations. Another two categories, radical and evolutionary innovations, related to the level of novelty of the fruit innovation. Characteristics important for the adoption of each of these categories are given.The results will be used for further, more quantitative, research

On the "association between two things":the case of student surveys and classroom observations of teaching quality

This study examines the association between two measures of teaching effectiveness—a student survey measure and a classroom observation measure—to determine whether their correlation depends on the study design. The sample includes 160 classroom observations of 56 teachers across 15 classes, in which students also rated the teachers with a survey. Dependencies are examined using generalizability theory. Results suggest that the correlation between the survey and observation measures depends on the number of classroom observations, the number of student ratings, and whether the designs are nested or partially nested. The effect is substantial: Predicted correlations range between 0.10–0.80 for the same variables with different study designs. In particular, the number of classroom observations has a notable influence, such that across all investigated scenarios, the correlation doubles when observers visit three lessons instead of one. Correlations also tend to be positively biased when research designs are nested

Het verplichte ouderschapsplan: regeling en werking

Antokolskaia, M.V. [Promotor]Coenraad, L.M. [Promotor]Niemeijer, E. [Copromotor

Biologische beheersstrategie van Valse Meeldauw in zonnebloem

Zonnebloemen zijn een belangrijk onderdeel van het biologische boeket. Echter de teelt van zonnebloemen wordt bedreigd door valse meeldauw. De Latijnse naam van valse meeldauw is Plasmopara halstedii). Deze oömyceet infecteert de zonnebloem systemisch en dit leidt tot grote verliezen. In dit project is gekeken naar verschillende manieren om valse meeldauw in de biologische teelt te beheersen. Zo is er gekeken naar teeltmaatregelen als het gebruik van pluggen en biologische grond ontsmetting. Verder is er gekeken naar een methode om de infectiedruk van een perceel met behulp van een biotoets vast te stellen

Biologische beheersstrategie van Valse Meeldauw in zonnebloem

At the moment downy mildew is the most urgent problem in sunflower cultivation in the Netherlands. Because sunflower is one of the basic products in the organic flower bouquets it is important to solve this problem. Downy mildew is caused by the oomycete Plasmopara halstedii. The initial infection comes from the soil where oospores can survive for up till 10 years. For now the only way for producers of organic sunflowers to control the mildew is to use a very broad crop rotation or use fresh land every year. The aim of this project is to test a biological control strategy in a practical situation in order to successfully control downy mildew originating from the soil. The first strategy tested was the use of a compressed plug of potting soil. Young sunflower seedlings are most susceptible for downy mildew infections and the use of a plug could prevent infection during the early growing phase. Unfortunately, due to the lack of infection in the field trials no conclusions on the effects of the use of these plugs can be drawn. The second strategy was to determine the risk of infection by analysing the soil of the field for infection with Plasmopora before sowing sunflower. Different sampling methods were tested in a bioassay. However, the infection percentage was to low to draw any conclusions. The third strategy was to use biological soil desinfestation as a control strategy for downy mildew. The principle of this method is to create a rapid oxygendeficiency in the soil which a lot of micro organisms do not survive. The oxygendeficiency is created by ploughing fresh grass through the soil and covering the plot with plastic non permeable for oxygen. This method appeared to be very effective in controlling downy mildew and is recommended to growers