Hi, we are also experiencing a big difference in numbers between Piwik and another log analyser, Webabacus.
We want to adopt a new web stats tool and have chosen Piwik so we’ve been running it on two of our high volume sites for almost a year now and are really impressed with it. However the figures generated by Piwik differ considerably to Webabacus. Piwik consistently tracks a third less unique visitors than Webabacus. We’ve identified certain factors which would account for some of the differences e.g 301 redirects, RSS feeds, direct hits to PDFs etc, Javascript disabled, pages not fully loading, time zone differences etc. However on every page, Piwik reports at least a third less than Webabacus. Webabacus uses the Spider and Robot Exclusion list from ABC to filter out the main bots so this difference should be minimal. I’ve done a line by line comparison, comparing IP addressees tracked in Piwik and logged by Abacus for individual pages and there is nothing obvious that points to why Piwik hasn’t tracked a third of the IPs reported by Webabacus. I know there will be inevitably be a 5-10% difference between a page tagging solution and a log analyser but I wasn’t expecting a consistent 30% difference. I’ve looked at previous posts on the forum to help but still haven’t identified the issue. I would be very grateful if you could offer any further suggestions?
Thanks!