Wikipedia:Mouse

When looking at potential vandalism, a helpful mnemonic is "MOUSE." Not only will it help you assess potential vandalism, but it will also help you assess whether the user is likely to cause trouble in the future


 * M is for Malice: Is the edit obviously malicious and disruptive or contentious, yet not overtly disruptive?
 * O is for Obstinate: Is the user repeatedly making the same edit despite warnings or reverts?
 * U is for User: Is the user who made the edit known for vandalizing in the past? Has the user been warned recently or sanctioned in a relevant way?
 * S is for Sources: Is the edit sourced? Is the source reliable and not blacklisted?
 * E is for Experience: Is the user a newbie who just made a test edit, a random IP address, or a long-standing editor who should know better?

These factors will help you assess whether an edit is vandalism and, if it is, whether to warn the user or escalate it to an administrator