**5. Discussion**

So far, we have shown the effect on the change in profit and the waste ratio of three supply chain flexibility strategies: (1) lead-time reduction, (2) quantity-flexibility contracts, and (3) multiple sourcing. The numerical analysis of lead-time reduction shows that when a firm reduces its lead-time by utilizing an onshore supplier instead of an offshore supplier, the firm can achieve both profit increase and waste reduction due to the decrease in demand uncertainty at the order time. When *t<sup>s</sup>* is greater than 0.29, the firm starts experiencing a positive change in profit, which exceeds 50% as *t<sup>s</sup>* increases to 1. As for the waste, even if *t<sup>s</sup>* = *t<sup>l</sup>* = 0, the firm still experiences waste reduction of 20% due to the increased cost, which lowers the newsvendor order quantity. The waste ratio decreases to zero as *ts* increases to one, since the actual demand is known at this point and the firm does not operate under demand uncertainty anymore.

If firms cannot order from an onshore supplier, they can still benefit from the flexibility of an offshore supplier with a quantity flexibility contract where, up to time *t<sup>s</sup>* , the firm can still adjust its order quantities by a factor of *α*. For a fixed *t<sup>s</sup>* , our analysis shows that firms can achieve a 30% increase in profit, and waste reduction can reach more than 50% as the flexibility parameter increases to 1.

For multiple sourcing, the numerical analysis is performed based on the selling price of the product. It shows that doubling the selling price from USD 150 to USD 300 results in a profit increase of almost 190%. The waste, however, does not change with different pricing as it is calculated based on the offshore order quantity, which is independent of price.

The selection of a given flexibility strategy is also dependent on the risk associated with it. On the one hand, although single sourcing with lead-time reduction has the highest effect in reducing waste while still increasing a firm's profits, it can amplify the exposure to risk in the presence of uncertainty. On the other hand, multiple sourcing can present higher costs, and this is not accounted for as a result of having to manage several suppliers [26]. It is therefore critical for firms to assess all the benefits and risks arising from choosing a specific strategy in pursuit of improved sustainability and profits.
