By John S. McClenahen Right now filings for unemployment insurance from striking California grocery workers are masking "the slow downtrend in claims that signals a modest improvement in U.S. job markets," contends Maury Harris, chief U.S. economist at UBS Investment Research, New York. More data, including October payroll employment numbers due to be released by the U.S. Labor Department on Nov. 7, are needed to really know whether or not the labor market is truly improving. In the meantime, initial jobless claim figures remain below 400,000, suggesting the labor market is less soft, even if it is not creating a lot of new jobs. For the week ending Oct. 25, initial claims for unemployment insurance totaled 386,000, some 5,000 fewer than the previous week's revised figure of 391,000, the U.S. Labor Department reported on Oct. 30. The department's four-week moving average, which smooths out week-to-week changes in initial claims, also continues to fall. Last week it was at 388,750, a decrease of 4,750 from the previous week's revised average of 393,500.