Theoretical sampling and interviewing technique

One of the distinctive features of grounded theory is that its sample relies on theoretical considerations rather than statistical considerations (Bryman, 2012). This means that the sample size cannot be pre-determined in advance. Instead an on-going and iterative sampling technique called ‘theoretical sampling’ is employed. Glaser and Strauss (1967, p. 45) define theoretical sampling as a “process of data collection for generating theory

whereby the analyst jointly collects, codes, and analyses his data and decides what data to collect next and where to find them, in order to develop his theory as it emerges”. After initial data collection and analysis was completed, the study employed theoretical sampling to determine who to sample next and what questions to ask during interviews, until theoretical saturation was achieved. Therefore, at this stage, the researcher did not adhere to the semi-structured interview guide used for initial data collection any longer. Questions were continuously modified or altered based on prior data analysis and depending on information needed for data comparison and saturation of categories. Table 3.5 provides an overview of the sample characteristics of this study.

In addition, the selection of potential interviewees was not pre-determined. Instead data collection was controlled by emerging theoretical categories, in the course of analysing data that have been collected. So for example, interviewee no. 4 (in Table 7) is a project manager who was asked to talk to the researcher about practical examples of waste or value-loss that he as a project manager believes are challenging, repeated or are typical in projects that he is engaged in. So his response was as follows:

“There is one point which in my experience that each and every construction site suffers. It is about recesses…Recesses in walls, in brick works, ceilings and so on. So it is exactly the interface between the technical parts of the building and the civil works or the plastering works or whatsoever. And during the planning stage, the design and planning team is stinging-off the pipes and the cablings and so on. And building up and designing special ways. Usually they are not able to put the recesses in aright order or in the right size. And usually they are making them much bigger. And when it comes to the execution, in some cases they are either in the wrong place because the contractors coordinated their works on-site with the construction management, and then they shifted some parts of the installations, and so recesses are not in the right place” (Certified senior project manager, 3rd November, 2015, Skype interview).

As a result, the researcher asked more probing questions in relation to the context of the situation, consequences of the incident, and possible root-causes of the problem from

the interviewee’s perspective. When asked about whom he believes to be mainly responsible for the occurrence of this typical example of value loss relating (i.e. inaccurate design and installation of wall recesses), his answer was as follows:

“I would say that the answer is of the designer. Once there is a problem on site and I tell him it was your fault as you did not consider that and that and that, and he would say (the usual answer is) I did not have that information at that point in time. This is the most common answer I would get; and, and in most cases, he is right! And that is what the partnering and collaborative methods try to minimise - That these information are really lacking at that point, at that moment, the design documents are prepared” (Certified senior project manager, 3rd November, 2015, Skype interview).

The data collection, coding and analysis there guided the researcher to decide to interview a senior designer for deeper investigation and data-comparison purposes. Therefore, based on theoretical sampling principles, the following interview was arranged and conducted with a senior architect and a director of framework arrangements in a leading construction company. The interviewee was informed about the story related to the design and installation of recesses and asked whether he experienced a similar situation. The interviewee’s response came as follows:

“Yeah, yeah I would say that's fairly common. I would push it a lit bit further back. It is not the designers that are the problem; it is the client. The client is not prepared to pay for the detailed design and investigation that might be needed to be able to get things right. I think part of the problem as well is lack of integration in the team. So I'll split into two issues: one is design coordination and the other one is actually incomplete design” (Head of Innovation and Director of National Frameworks (Senior Architect), 8th November, 2015, Skype interview).

Consequently, the rest of the semi-structured interview with the senior architect focussed on investigating factors that lead to poor design coordination and incomplete design from the participant’s point of view, in addition to a number of other questions

that emerged from data analysis of previously collected and coded data. This evolving process of interviewing and coding and analysis of data continued till the study reached a state of theoretical saturation.

Table 3.5: Sample information

Seq. Professional Role / Title duration (mins)

Data collected

1 _{Turnaround Project Manager 100 S+E}

2 _{Senior Consultant (FICE) 69 P+E+D}

3 _{President of a lean consultancy company 60 S}

4 _{Certified Senior Project Manager (PMP, MRICS) 65 S+E} 5 Head of Innovation and Director of National Frameworks

(Senior Architect)

57 S

6 _{Project manager - Subcontractor 51 S}

7 _{Head of Supply-chain at a leading contractor 60 S}

8 _{Senior Procurement and Performance Consultant (PhD) 90 P} 9 Managing Director and Principal Consultant at a Rail

consultancy company

50 S

10 _{Senior QS at a leading contractor 39 P}

11 _{Site manager working for small contractor and Lean Specialist} 75 S

12 _{Senior Cost Consultant (MRICS) 56 S}

13 Director and Project Manager at a specialist subcontractor (Trenchless drainage repairs)

33 P

14 _{Senior Design Coordinator at a leading contractor 45 P+D} 15 _{Business Development Manager at a major contractor 30 P}

16 _{ECC Project Manager (CEng, MICE) 36 P}

17 _{Senior Architect & BIM Manager (MCIAT, PMP) 45 S}

18 _{Site Agent (CEng) at a leading contractor 40 P+F+D}

19 Associate Director at a leading cost consultancy and QS

company – Financial governance 35 P+D

20 _{Deputy ECC Project Manager (CEng, MICE) 33 P+E}

21 _{Sub-agent at a leading contractor}

27 (S+E+D) 22 _{Project Planner agent at a leading contractor}

23 _{Principal Design Engineer 40 P}

24 _{Senior Project Manager and Consultant 15 P}

* Seq.= sequence; S= skype video interview, P= phone interview, E= follow-up questions by e-mail, F= follow-up by phone , D= supporting documents sent by e-mail

This study relied on the use of qualitative semi-structured interviews, as part of an adapted grounded theory methodology, instead of participant observations. Each of these two contrasting methods has its own merits and demerits. However, there are a number of issues which can make qualitative interviewing exhibit advantages over participant observation. For instance, in this study, there are various issues that are simply not amenable to observation, so that asking participants about them represents the only possible means for finding about them within a qualitative research approach. Examples of these include issues associated with commercial sensitivity, reasons for inclusion of special contractual clauses, opportunistic practices, contingency values and so on. Other important factors include: ethical and confidentiality considerations, allowing for reconstruction of events, avoiding reactive effects due to observation, and greater breadth of coverage in terms of access to wider variety of situations and people (Bryman, 2012, pp.495-496).

The two main options for conducting qualitative research interviews are face-to-face or by telephone. The former is the most common, and probably the best, mode in which to conduct interviews (Oltmann, 2016). However, telephone interviewing is likely to have certain advantages when compared to face-to-face interviewing (Irvine et al., 2010); most obviously, minimal travel time and cost. Furthermore, using telephone interviewing can be a more effective mode when asking sensitive questions, as it can help interviewees to feel less intrusive or distressed about answering when the interviewer is not physically present (Bryman, 2012, p. 488). However, there are a few concerns related to lack of ability to access visual or non-verbal cues and technical issues associated with quality of phone line (Irvine et al., 2010).

At the same time, advances in technology and internet-based methods of communication are becoming increasingly important and popular in qualitative social science research. According to Sillivan (2012), the use of video conference can allow researchers to interview a wide range of geographically dispersed individuals with a recorded interaction that at least mimics face-to-face interactions. Based on these considerations, this research study conducted interviews via telephone and Skype video- conferencing rather than face-to face-meetings, as shown in Table 3.5 above. Skype

video conferencing was the favoured approach; however telephone interviews were conducted when this was not possible.

On some occasions, follow up questions were sent to participants by e-mail or discussed through the phone, when needed, to ask for clarifications on the accuracy of unclear parts of transcriptions or when the researcher needed the interviewees to probe on some of their answers provided during interview. Although, Forbes and Henderson (2005) advise researchers to take careful considerations about the ethical and epistemological implications of sharing transcripts with participants, the experience in this study has been quite different and positive. First of all, the researcher did not share full transcripts with participants. Instead, participants were only asked to check the accuracy of the researcher’s transcription to very few words or sentences. Therefore, the aim in this case was to avoid guessing, and thus ensure accuracy of meanings and interpretations. On other case, the aim of these follow ups was to ask participants for more detail or to request for supporting evidence or documents. This practice is encouraged by Charmaz (2006) as it aligns with her recommended intensive interviewing technique for grounded theory studies. Examples of supporting documents received from participants include:

 Form of agreement and contract data of an ongoing infrastructure project (268 pages)

 Samples of planning sheets related to resource quantities and scheduling

 Samples of weekly work plans and consolidated as-built Percentage Plan Completed (PPC) charts and diagrams, including analysis of reasons for non- completion (RNC).

 Template of tool-kit used for measuring supply-chain performance

 Power-point presentation about a leading consultant firm’s strategy and major commercial services