In previous research on rubber supply, Purcell (1993) studied the factors
affecting the rubber supply from Sarawak by using a cointegration method and
causality tests to determine the relationship between rubber production, price, area,
and labor. The results showed that rubber supply was affected by the area planted to
rubber and price. The area planted for rubber is affected by price and labor factors.
Prices have affected the rubber supply. These results can be used as a guide in a
reflection of global supply trends affecting prices.