CPV 85300000 is a group — the three-digit level of the Common Procurement Vocabulary — covering social work and related services. It sits inside division 85, health and social work services, and narrows it to this particular category.
A contracting authority classifying a tender picks the most specific code that describes what it is buying, so contracts in this group appear with eight-digit codes beginning 853. Searching on the three-digit prefix catches all of them at once, which is why alerts are usually better set at this level than on one exact code.
Every CPV code is eight digits followed by a check digit after a hyphen, and the digits narrow from left to right: the first two are the division, the third marks the group, the fourth the class and the fifth the category, with the remaining digits available for finer distinctions. Trailing zeros mean "no further detail", which is why the division 85 is written 85000000 rather than just 85. The check digit is a validation digit only — it carries no meaning about what is being bought, and notices sometimes omit it.
CPV codes are language-independent: the same code means the same thing in a Polish notice as in a Finnish one. That makes searching by code far more reliable than searching by keyword across markets, where the same work is described in a dozen different languages and wordings. It is also why a buyer's own description of a contract is a poor filter and the code is a good one.
A notice carries one main CPV code and may carry additional ones for the other things the contract covers, so a contract classified elsewhere can still involve social work and related services. When you set up alerts, match on the shortest prefix that still describes your work: too specific and you miss contracts a buyer classified one level up, too broad and you read a great deal that does not apply to you. The live counts below show where contracts under this code are actually being published.
