In many ways, it is easier to use quantitative techniques for research, as long as you follow the structures and guidelines for setting them up. The difficulty with quantitative techniques is that the results do not have context. The context provided with qualitative research provides some insight into its validity. With quantitative techniques, numbers are often shown for how big an effect is, or how often something happens without describing how they were gathered or calculated. These numbers rely on careful data gathering and use of the correct statistical techniques for the size and shape of the population.
If you have analytics based on actual usage of a website, this provides some reliability, as the numbers come from people who are actually using your product. However, if you gather quantitative values through usability testing or surveys, the metrics that you use to gather the data and the sample of people that you test with is often hidden. This information...