Well, according to this source:
"Chet Ubowski of the Colorado Bureau of Investigation concluded that the evidence fell short of that needed to support a conclusion that Mrs. Ramsey wrote the note. (SMF 197; PSMF , 197.) Leonard Speckin, a private forensic document examiner, concluded that differences between the writing of Mrs. Ramsey's handwriting and the author of the Ransom Note prevented him from identifying Mrs. Ramsey as the author of the Ransom Note, but he was unable to eliminate her. (SMF 198; PSMF 198.) Edwin Alford, a private forensic document examiner, states the evidence fell short of that needed to support a conclusion that Mrs. Ramsey wrote the note. (SMF 197; PSMF 197.) Richard Dusick of the U.S. Secret Service concluded that there was "no evidence to indicate that Patsy Ramsey executed any of the questioned material appearing on the [R]ansom [N]ote." (SMF 200; PSMF 200.)
During the investigation, the Boulder Police Department and Boulder County District Attorney's Office consulted at least six handwriting experts. (SMF 1 191; PSMF 1 191.) All of these experts consulted the original Ransom Note and original handwriting exemplars from Mrs. Ramsey. (SMF 205; PSMF , 205.) Four of these experts were hired by the police and two were hired by defendants. (SMF , 191; PSMF , 191.) All six experts agreed that Mr. Ramsey could be eliminated as the author of the Ransom Note. (SMF 194; PSMF 194.) None of the six consulted experts identified Mrs. Ramsey as the author of the Ransom Note. (SMF 195; PSMF 195.) Rather, the experts' consensus was that she "probably did not" write the Ransom Note. (SMF , 196; PSMF 196.)14 On a scale of one to five, with five being elimination as the author of the Ransom Note, the experts placed Mrs. Ramsey at a 4.5 or a 4.0. (SMF 203; PSMF 203.) The experts described the chance of Mrs. Ramsey being the author of the Ransom Note as "very low." (SMF . 204; PSMF 1 204.) The two experts hired by defendants both assert that this evidence strongly suggests that Mrs. Ramsey did not write the Note. (SMF 254.)"
http://www.acandyrose.com/03312003carnes21-30.htm
With a score of 4.0 to 4.5 on a scale of 1 to 5, with 5 equating to
elimination, there appears to be an 80 to 90% chance that Patsy did NOT right the note.
Ergo, the weight of expert opinion suggests that Patsy did not write the note, and since she is the only member of the Ramsey household that was not ruled out entirely, it appears very likely that no member of the Ramsey household wrote the note and that the note was therefore written by an intruder.
I realize that there have been other analyses which concluded that Patsy is the author, but they are highly suspect as they appear to have been performed at the behest of parties with a vested pecuniary interest in the final conclusions of the analyses, such as winning a libel suit or selling a book.