What is the difference between the objective, noted observations of a nurse in the case of Ares v. Venner, and the subjective comments of the nurse in that case?

I have described in some detail the particular circumstances which gave rise to the decision in Ares v. Venner, supra, in order to illustrate the contrast between the objective, noted observations of the nurse in that case and the subjective comments of the various authors of the documents under consideration for admissibility in the instant case. Some of that subjectivity may also arise due to the absence of two of the elements essential to the admission of documents under the principle in Ares v. Venner - those of personal knowledge and contemporaneous observation by the maker of the document.