I hadn’t really thought about that question until I came across this article.
According to this article, many diaper manufacturers try to make a “cheaper” diaper that only ends up last 3-4 hours, however this is not how a typical diaper should be. The reason many of these companies do this is because it allows higher product turnover which results in greater profit, so it is important to be aware of these kinds of things in order to be able to tell quality over quantity when looking for diapers.
The author this article makes a point that many of the European diapers are made more to the true diaper wearer and they normally last anywhere from 8-12 hours. Wow! I have to say that is very good, I don’t think I even usually make them that long! The example that he uses in this article is Secure X-Plus Adult Undergarments. I’m sure there are many different kind but this is just the example that is used in the article.
This author also makes some very good points about the product design of many diapers. The Super Absorbent Polymer (SAP) is used in the diapers that are more absorbent. This makes sure that the diaper can absorb multiple wettings. I have never heard of this before, but maybe if you can find out if this is in the diaper then you will know if this has greater absorbency!