Black Friday's retail sales have been tallied, and the results continue to show the difficulties in predicting consumer spending. Best Buy (NYSE:BBY) and Circuit City (NYSE:CC) posted strong sales of high-ticket items such as flat-panel TVs and digital cameras, but broad-based retailer Wal-Mart (NYSE:WMT) forecasted tepid sales for its wares. The divergence of performance between these retailers highlights the challenges investors face when making investment decisions based on top-down or bottom-up analysis.

I believe that Wal-Mart's results bolster recent top-down analysis, which advises investors to avoid consumer discretionary businesses, citing high energy costs, rising interest rates, and a collapsing housing market, among other factors. Wal-Mart is hardly facing this music alone. Many retailers have faced low-to-negative same-store sales and compressed profit margins. In particular, the entire home-furnishing retail segment has struggled, including historically strong performer Bed Bath & Beyond (NASDAQ:BBBY).

But if you wrote off consumer spending en masse because of a difficult macroeconomic environment, you'd have missed at least one retail segment, electronics, which has performed quite well. Strong discretionary spending for flat-panel TVs or digital cameras hardly suggests that consumers are struggling to pay their utility bills.

Surprisingly (at least to this Fool), Best Buy and Circuit City are outperforming Wal-Mart and fellow competitor Target (NYSE:TGT) in the stock market, even in the face of such negative macroeconomic prognostications. There must be other forces at work driving these two companies' success.

A successful investor must find the key factors or trends that will drive an investment's performance. Focusing on the macro or micro picture alone isn't enough. The relevant information can only be gleaned by looking at the complete picture. Just as the yin completes the yang, bottom-up analysis completes top-down analysis.

For related retail yins and yangs:

Best Buy is a Motley Fool Stock Advisor pick ; Wal-Mart made the cut at Motley Fool Inside Value ; and Bed Bath & Beyond has been selected by both those newsletters. Try any of our Foolish investing advice services free for 30 days.

Fool contributor Matthew Crews welcomes your feedback -- really! He has no financial position in any of the companies mentioned. The Motley Fool has an ironclad disclosure policy .