Prompt cards can help pupils perform better during a task because they make it easier to retrieve information. This probably applies to all pupils, including when reading and writing. However, this has not been specifically investigated for Grade 1.
Performing better does not automatically mean that pupils are also learning better. If pupils continue to use prompt cards when they no longer need them, they may become dependent on the aid and rely less on their long-term memory. In the long term, this may lead to less learning.
Prompt cards therefore appear to be most effective as temporary, targeted support. They are best used with pupils who are not yet able to complete an assignment independently. The support should be tailored to the individual pupil's needs, so that they can practise independently without too much assistance.
As pupils become more skilled, it is important to gradually phase out the prompt cards. This encourages pupils to rely increasingly on their own knowledge and skills. Phasing them out does not have to follow a fixed schedule: the teacher can determine for each pupil and each task when support is still needed.
This requires teachers to continually assess what pupils can do independently and when a prompt card is needed. It is also important to explain to pupils how to use the cards and encourage them to do so consistently. In short: prompt cards are probably most valuable when they are used temporarily and tailored to the individual pupil, and are then gradually phased out step by step.
You can read the full answer from the Kennisrotonde of the National Knowledge Institute for Education here.