 However, the policy potentially discouraged investors from building new rental units.A 2000 study that compared the border areas of four California cities having vacancy control provisions (Santa Monica, Berkeley, West Hollywood, East Palo Alto) with the border areas of adjoining jurisdictions (two of which allowed vacancy decontrol, including Los Angeles, and two of which had no rent control) showed that existing tenants in the vacancy control cities had lower rents and longer tenure than in the comparison areas.Thus, the ordinances helped protect the existing tenants and, therefore, increased community stability.