How can I compare a the size of a gui with the absolute size of the gui?

I'm trying to make it so if the gui is the same size as the screen (X), it will change the text to "Thanks!"

correct = UDim2.new(0,0,900,0)
if script.Parent.Parent.Parent.Bar.Size.X > correct then
    script.Parent.Text = "Thanks!"
end

This doesn't work and I get an error that says: "Players.Player.PlayerGui.ScreenGui.Frame.status.Script:4: attempt to compare two userdata values"

How can I get this to work?