A few things to note:
- IVAD is more and more "the government pollster." A month before the 2007 constitutional reform referendum, they had the Sí ahead 64%-28%. This time around, it was Information Minister Jesse Chacón who made their poll result public.
- CECA is a small firm without much of a track record. In November, 2006, they had Manuel Rosales edging ahead of Chávez for the presidency. This poll used a very small sample (242 interviews in big cities) which yields a massive +/- 6.3% margin of error.
- I haven't been able to get my hands on Schemel's slides, just an UnionRadio write-up, so I don't know the size of Hinterlaces's sample or when exactly they were out in the field. Schemel is, in any case, Globovision's pollster.
The firm with the best forecast of the 2007 referendum outcome was Datos, and they've not been heard from this cycle.
There's no way around it, it's just a data-poor environment.
(As always, if you've seen a published poll I missed, send it along.)