"Investors are once again crowding into fewer and fewer stocks, bidding their prices to levels where no errors are acceptable," notes A. Gary Shilling, president of the Manhattan-based asset management firm that bears his name. "When investors concentrate on a tiny fraction of stocks and neglect the rest, as they did before the Dow declined 45 percent in 1973-74, they're telling you they don't like the economy. And when the economy recedes, few stocks avoid the downdraft."

- Growth funds don't come more conservative than Value Line Fund. It buys only stocks rated 1 or 2 for timeliness by the widely respected Value Line investment service. The fund further pares this 400-stock list by insisting on lower price-earnings ratios, better price momentum, higher liquidity and less institutional ownership than Value Line's average. This cautious approach to growth has produced 14.1 percent average gains the past five years. Recent favorites: Abbott Labs, Baker Hughes, Eli Lilly, G.E., Halliburton, Home Depot, U.S. Surgical, UST, Wal-Mart, Waste Management.- Scientists haven't yet found cures for autoimmune diseases, but some very large drug markets have been created for the treatment of their effects, says Medical Technology Stock Letter (P.O. Box 40460, Berkeley, CA 94704). "These diseases include: rheumatoid arthritis, juvenile onset diabetes, inflammatory bowel disease, multiple sclerosis and systematic lupus erythematosus. This is an exciting research frontier, which will provide substantial profits for numerous biotech companies." MedTech's favorites: Greenwich Pharmaceutical, Immunex, Synergen, XOMA.

- "A high-yield value methodology has always outperformed a bear market," observes Tom Broadhus of T. Rowe Price's Equity Income Fund. "You're buying high-quality, less volatile stocks cheap." Financial World magazine recently sent its computers in search of such quality value and found nine low-risk stocks with strong earnings, assets and cash flow, yields of more than 6 percent and single-digit p.e. ratios: Briggs & Stratton, K mart, Kaman, Kellwood, Oxford Industries, Sears, Thomas Industries, Union Carbide, Witco.

- Investors can no longer count on gold stocks to move independently of the rest of the market, thus providing portfolio diversification. According to a recent study by professors Jess Chua, Gordon Sick and Richard Woodward of the University of Calgary, gold stocks showed only a 24 percent correlation to the S&P 500 in the '70s. But this figure almost doubled, to 42 percent, in the 1980s.

- Roughly 40 percent of all municipal bonds outstanding could be called by 1996 to take advantage of lower interest rates. Massachusetts Financial Services recommends several strategies to guard against such a possibility: 1) Swap existing holdings for new bonds with close to 10 years' protection against calling; 2) buy non-callable bonds; 3) buy bonds selling at deep discounts to their face value.

- Do you feel like you always get into the stock market at the top? According to a new Sanford C. Bernstein & Co. study, it doesn't matter as much as you might think. The study found that $2,000 invested in the S&P 500 Stock Index at its highest price level each year over the past two decades would be worth $172,000 now, or $132,000 more than the total amount invested.

Investor's Notebook reflects the opinions of professionals. It does not endorse specific investments, and no endorsement is implied or should be inferred. For more information, contact the individual firms cited.