Final answer:
The recommendation by David Arnold to not assess a particular market in isolation is key for companies conducting global market research, as comparative assessments and a broader perspective are essential for gaining accurate insights.
Step-by-step explanation:
Among the options provided, the recommendation by expert David Arnold that is not advisable for companies engaged in global market research is to assess a particular market in isolation. It is crucial for companies to understand that in today's interconnected global economy, conducting market research requires a broader perspective. Companies need to utilize multiple indicators and develop customized measures that are specific to their industry or product. Furthermore, conducting comparative assessments in neighboring countries can provide valuable insights and help in understanding regional dynamics.
However, assessing a market in isolation can lead to a lack of understanding of the broader context and inter-market relationships. This isolated approach goes against the practice of using comparative assessments and does not take into account the influence of surrounding markets. Moreover, it is important to understand that different research methods, like observation and surveys, have their own strengths and weaknesses, and relying heavily on just one, such as observation over statements of purchase intention, may limit the comprehensiveness of the findings.