Final answer:
The most critical characteristic ensuring that working papers achieve their primary purposes is that they must provide sufficient, reliable, and useful information to support the engagement results. The correct option is 1.
Step-by-step explanation:
When considering the characteristics of working papers that ensure they achieve their primary purposes, it is crucial to recognize the variety of factors that contribute to their effectiveness. However, among the given options, the most critical aspect is that working papers must provide sufficient, reliable, and useful information to support the engagement results. This requirement is fundamental because the core purpose of working papers is to document the evidence and reasoning that underpin the conclusions and recommendations of an engagement.
While having a standard format (option 2), arranging papers in a logical order (option 3), and proper indexing and cross-referencing (option 4) are all important characteristics that can enhance the utility and comprehensibility of working papers, they are secondary to the need for the content to be of high quality and substance. Ensuring the reliability and relevance of information is paramount because it directly impacts the credibility and integrity of the engagement's outcome. This aligns with the principle that every point made in a paper should be meaningful and support the paper's overarching claim or thesis.
To conclude, among the options, the correct option in the final answer is that working papers must provide sufficient, reliable, and useful information to support the engagement results. This encompasses the core requirements for effective documentation in any professional field, serving as evidence that the preparer understands the material and has conducted thorough research while presenting trustworthy information. Accordingly, this approach adheres to the ultimate goal of these documents, which is to substantiate the work performed and support the findings put forward.