title_body: Did a majority of followers of Ido indeed switch over to Occidental? The Wikipedia article on Occidental/Interlingue says (in this version):
  
  
    According to the Occidental magazine Cosmoglotta in 1928, a majority of Ido adherents took up Occidental in place of Ido.
  
  
  Obviously, Cosmosglotta isn't an unbiased publication venue. Is there any independent evidence that this switching of language actually took place?
upvoted_answer: I'm as pro-Occidental as they come (it's the only auxiliary language that I support) but I came across that article in 1928 during my typing up the archives of Cosmoglotta and that article is nothing more than Ric Berger wishful thinking. He unfortunately spent just as much time attacking Ido as he did supporting Occidental, and kept on proclaiming it to be moribund and ready to collapse for some 20 years.
  
  Here's the article in question that he wrote in 1928 on the Ido conference from which he concluded that Ido was on its last legs:
  
  http://cosmoglotta.pbworks.com/w/page/132587775/Cosmoglotta%20A%20053%20%28oct%201928%29 (Title: Raport del Occidental-Observator Ric. Berger al Association «Cosmoglotta», Wien.)
  
  So the answer is no. However, it's also true that the majority of the Occidentalists at that time were once Idists, from Berger to Gär to Ramstedt to Pigal to de Guesnet and all the rest. There was definitely a large influx from Ido to Occidental, and Occidental as far as I can tell was the most active auxiliary language after Esperanto by the late 30s and into the 1940s. Matejka and Berger had a lot of back-and-forth in the 1920s to early 1930s until Matejka decided to move over to Occidental, which he stayed with until his death in the late 1990s. He's probably the most prominent example of a major Idist who went full in on Occidental. But Berger hadn't taken into account the other source for new Idists, namely new users who weren't satisfied with Esperanto but still liked the overall concept (i.e. the people that thought that Zamenhof almost got it right).
  
  Anyhow, I removed that sentence from Wikipedia last year when going through the Cosmoglotta archives because it certainly isn't backed up by anything besides Berger's wishes.