I have a list with a single line text field - [title]. Due to users being difficult, I now need to tighten this field down and only allow them to enter certain options. I was trying to do this via column validation but am running into syntax errors.
What is allow certain options mean, if it is fixed, hide the title column and create a new choice field. If you have dynamic or dependent options that vary with something else, then attach an event receiver using C# and perform a validation on itemadding event.
Also if you use SharePoint Designer, there will be are ways to edit the default form to add validations.