The bullwhip effect is the phenomenon of increasing demand variability in the supply chain from downstream echelons (retail) to upstream echelons (manufacturing). The objective of this study is to document the strength of the bullwhip effect in industry-level U.S. data. In particular, we say an industry exhibits the bullwhip effect if the variance of the inflow of material to the industry (what macroeconomists often refer to as the variance of an industry's "production") is greater than the variance of the industry's sales. We find that wholesale industries exhibit a bullwhip effect, but retail industries generally do not exhibit the effect, nor do most manufacturing industries. Furthermore, we observe that manufacturing industries do not have substantially greater demand volatility than retail industries. Based on theoretical explanations for observing or not observing demand amplification, we are able to explain a substantial portion of the heterogeneity in the degree to which industries exhibit the bullwhip effect. In particular, the less seasonal an industry's demand, the more likely the industry amplifies volatility--highly seasonal industries tend to smooth demand volatility whereas nonseasonal industries tend to amplify.bullwhip effect, production smoothing, supply chain management, volatility

A disruptive innovation (i.e., one that dramatically disrupts the current market) is not necessarily a disruptive innovation (as Clayton Christensen defines this term). To aid in understanding why some innovations are more (or less) disruptive to the long‐term health of incumbents, this article offers terminology and a framework complementary to Christensen's work, focusing on the diffusion pattern of the new product. The framework and model presented herein suggest that when an innovation diffuses from the low end upward toward the high end, a pattern called low‐end encroachment, the incumbent may be tempted to overlook its potential impact. Three possible types of low‐end encroachment are illustrated: the fringe‐market, detached‐market, and immediate scenarios. Conversely, when the pattern is one of high‐end encroachment, the impact on the current market is immediate and striking. A three‐step framework is identified to assess the potential diffusion pattern and impact of an innovation, thereby helping a firm determine the threat or opportunity that an innovation represents.

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Past research (along with our experience) suggests that a firm's supply chain (i.e., value chain) plays an integral role in its ability to not only reduce cost via process innovation, but also in its ability to develop new products and services. Evidence suggests the value chain is playing an ever‐more‐important role, with greater prevalence of distributed product development (spanning geographic, organizational, or firm boundaries) and open innovation (performed outside the firm). We discuss some of the trends with regard to supplier and customer involvement in the innovation process, and summarize some of the research exploring the rationale behind those trends and the research offering advice on how firms can use external resources to further improve their innovation performance. We present a number of examples that illustrate some best practices.

Suppose you are a Marketing Manager envisioning a new product, or an Operations Manager contemplating a process improvement, or a CEO who commissioned an integrated new product development team. If our assumptions hold, our model offers you a single numerical measure, called the degree of product/process innovation, to determine your initiative's impact on potential sales, prices, market segments, and profits. Our simple, single-period model is a variation of the existing vertically differentiated products model: There are two competing substitute products, and customers will buy at most one of them. Our contribution is to allow new relationships between the valuations of the two products by potential customers, and to allow differing unit production costs. We identify equilibrium results when two competing firms each offer one product, and find the profit maximizing result when one (monopolistic) firm offers both products. The new product infringes on the market in one of two ways: High-end encroachment results when the new product attracts the best customers (those with the highest reservation prices), while low-end encroachment identifies a situation where the new product attracts fringe (lower-end) customers. Low-end encroachment may help explain why an incumbent sometimes fails to recognize the threat of an entrant's product, as we illustrate with an example from the disk drive industry. In short, we offer insight into the value of both a marketing objective (enhancing the product design attributes) and a manufacturing goal (lowering the production cost) in a product and/or process improvement project.degree of product/process innovation, low-end encroachment, high-end encroachment, reservation price, disruptive technology, operations strategy, vertically differentiated products