(1) Bidirectional supply chains are generally short
Single-level bidirectional supply chains consist merely of three stages: the transfer of customer inputs to the service provider, the processing by the service provider, and the transfer of the processed output back to the customer. With many services the supply chain is even simpler than that, since the three stages are simultaneous as far as service-provider involvement is concerned. For example, when a customer arrives at the barber for a haircut, he brings his hair with him. At the instant the service provider is cutting the hair, the customer is receivingdeliveryofthehaircut(whichistheconceptofsimultaneousproduction andconsumption).Theresultisanextremelycompressedsupplychain.