Survey Method

The main survey was conducted during February – April 2008 using paper based face-to-face residential interview. Prior to the pilot and the main survey, the interviewers were trained in the method to conduct the survey and briefed on health and safety matters with necessary personal safety system in place when conducting the survey. The candidate was involved in several aspects during the design and management of the survey¹⁶.

16 The candidate’s role in survey and management included survey and questionnaire design, preparing the questionnaire and the associated cards used during the survey along with forms for number of completed questionnaires and interviewers’ payment, employing and training interviewers and conducting health and safety inductions. The level of housing service charge generally levied in the area was also researched through the housing agents in the area as well as the service charge information provided in the various blocks of the site. Making arrangements for payments as well as travel allowances for the interviewers was also conducted by the candidate during the survey. Prior to the pilot survey, the survey site was well examined and blocks were identified where surveys would be conducted. Interviewers were also familiarised with the survey site and the different locations of the site (based on the nearest main traffic road). Initial letters were prepared informing the residents of the site on the survey with the tentative dates when it would be conducted in the blocks and these were then put into the residents’ letter box with the help of few other interviewers.

On each survey day, interviewers were assigned specific area and blocks where they would conduct the interviews and were handed the relevant list of apartments that were already interviewed in the blocks of that area. The candidate accompanied an interviewer (selected randomly or based on interviewer/survey requirements) every survey day during the pilot as well as the main survey. The purpose of accompanying the interviewer was to ensure the quality of the survey as well as to help the interviewer during the survey process by lifting the questionnaires, showing the choice cards to respondents etc. The candidate was present on the survey site at all times and days when the survey was conducted and acted as

A short pilot study over a period of two days with about 13 respondents was carried out in the area to test the effect of the questionnaire design. The main survey for the first phase was conducted between mid February to early March while for the second phase was conducted from late March to mid April. The surveys were mostly undertaken between 6:30 – 9:00 pm on weekdays and between 2:00 – 8:00 pm on weekends in order to have as much variety in respondents as possible. Only one respondent per household was interviewed.

The questionnaires and the associated choice cards were colour coded based on the experiment type (questionnaire and choice cards for each experiment were printed on different colour paper based on the experiment type) as given in Figure 5.2 for easy recognition during and after the survey. The survey site was divided into three parts based on the nearest main traffic road. As one of the questions was related to the respondent’s perception of noise in the apartments of the block in relation to one of the major traffic roads, the blocks closer to the periphery of the enclosed residential area, and hence nearer to one of the main traffic roads were selected for the survey. A minimum of 50 completed questionnaires were aimed for each of the experiment of each phase, thus bringing the number of respondents for each experiment at every specified site to about 17.

Blocks closer to the particular main traffic road were identified and each interviewer was given a set of blocks where they could undertake the survey. The interviewers were asked to keep a list of the block and the apartments, along with the information on which households have undertaken the survey. This was done in order to avoid repeating the survey in the same household. As only the households that participated in the survey were noted during the data collection process and

a site supervisor as well as a point of immediate contact for the interviewers in case of any needs/emergency. At the end of each survey day, the candidate also received feedback from the interviewers based on their experiences or comments from the respondents, discussed any important or relevant aspects with other interviewers as well as replied to any queries or doubts raised by the interviewers. The completed questionnaires of the day were then collected from the interviewers and sorted while the interviewers were asked to indicate the number of completed questionnaires on the relevant forms.

information on households that refused to the survey was not recorded¹⁷, the rejection rate cannot be estimated. The list of all the blocks and households that took part in the first phase of the survey was examined closely to identify the blocks and households for the second phase. For the entire survey, the aim was to interview a household only once though this had to be relaxed slightly in the second phase due to lower availability of respondents. In this case, some people who participated in the first phase of the survey had to be contacted to participate in the second phase. Though some interviews were conducted, the number of re-interviews were very few (seven out of 204 re-interviews obtained in the second phase) which amounted to about 3.4% of the sample size.

Before the pilot survey of the first phase, letters were sent out to the residents of selected blocks in the site, informing them of the tentative period when the survey will be undertaken along with the objectives of the survey. During the course of the first phase of the survey, it was learnt that this practice did not affect the respondent’s willingness to participate as those who did not receive the letter also seemed eager to take part in the survey, moreover the availability of respondents in their apartment was also not found to be significantly determined by the tentative survey period sent out in the letter. Hence this practice was discontinued for the second phase of the survey.

The questionnaire consisted of two parts: one, with the socio-economic, residential and noise characteristics of the concerned apartment and second, a set of choice cards for the SP exercise. The interviewer was asked to fill the questionnaire on the respondent’s behalf during the interview. During the SP exercise, the choice cards were offered to the respondents, one at a time, and the choice responses were noted in the questionnaire by the interviewer. The face-to-face interview allowed the respondents to discuss or clarify any issues that emerged during the process. The

17 The interviewers experienced that in some cases, the households’ willingness to participate in the survey depended on the person who answered the door-bell. Thus, in those cases, while a member of the household had refused to participate in the survey, another household member showed willingness to participate when asked on another day.

Also, when a household was unable to participate in the survey on a particular day when the interviewer was visiting the block, appointment was taken with the household member for another day and time when they would be able to participate. Thus record of households that definitely did not want to participate in the survey was not collected.

respondents were explained the meaning of the choice scenario elaborately in the beginning of the choice experiment and they were strongly encouraged to reply to all the choice experiment questions. When respondents could not reply to all the 16 choice scenarios of the choice experiment, the survey was terminated and not included in the data input process. Thus only those questionnaires which had all responses to the choice experiment section were regarded as a completed questionnaire.

While 55 completed questionnaires were obtained for experiments 1 and 2 of the first phase, 56 completed questionnaires were obtained for experiments 3 and 4, bringing the total respondents for the first phase to 222 while for the second phase, 51 completed questionnaires were obtained for each of the experiments bringing the total number of respondents to 204.