Do you know of any reputable Judiciary Independence Index?

Sir, you publish June 18 a long letter that signed by the Director of the Department of Information, Press Division, Ministry of Foreign Affairs, Bangkok, Thailand, purports that “Thai judiciary is independent” and I must confess I have no idea of how much credibility I should assign to it. Would you know about any reputable Judiciary Independence Index that I could use? I mean if I where able to get a grasp on where Thailand stands on this issue when compared for instance to my homeland Venezuela it would indeed be quite helpful.