Here is a 1-paragraph summary of the text: Bad data can have serious consequences in event streams, leading to incorrect decisions and significant negative impacts on business operations. To prevent bad data from entering an event stream, schemas are essential, along with testing, validation rules, and data contracts. These strategies significantly reduce error incident rates by preventing producers from writing bad data and making it easier for consumers to focus on using the data. By adopting these prevention techniques, businesses can save time and effort in dealing with bad data, and instead focus on getting actual work done with their data.