A survey was created to collect response on the socio-demographic, travel time, mode of transportation, duration spent in nature reserve, frequency and purpose of visit and willingness to pay.

A systematic random sampling was then conducted at each nature reserve where every third visitor was approached to administer the survey with an easily accessible QR code. Each survey was conducted at each nature reserve (Bukit Timah Nature Reserve, Central Catchment Nature Reserve, Labrador Nature Reserve and Sungei Buloh Wetland Reserve) between 0800 – 1200 on Saturdays and Sundays, spanning across two weekeneds.

The responses were then collated and analysed using the travel cost method (TCM) based on Grave (2013): 

V = [(T x w) + (D x v) + Ca] x Va

where T = travel time (h), = average wage rate ($/h), D = distance travelled (km), v = marginal vehicle operating costs, Ca = cost of admission to asset and Va = average number of visits per year. 

The travel cost method allows us to estimate the economic value of each nature reserve by looking at full travel costs, including time, of visiting each site. While there are no admission fees to our nature reserves, we asked respondents the amount that they are willing to pay.