Types of sampling

Before selecting the samples, the research classified which types of sampling techniques should be followed to ensure a valid scientific methodology. There are two major groups of sampling; the first is ‘probability sampling’, also known as random sampling; and this is where every member of the targeted population has an equal chance of being included. On the other hand, with ‘non-

probability sampling’ the selection from the population is made on the judgement of the researcher

and so it is inapplicable for generalising the whole population (Cargan, 2007). Each major group has different sampling types that follow a classification defined in the following table:

47 Type of

Sampling Definition and Purpose RELEVANCE FOR THE STUDY

A. Probability Sampling (Random and Equal chance)

Simple Random

A basic sampling design based on a single stage of selection from a sampling representing the whole target population.

The requirement for this study is to ensure that the findings’ credibility and validity through several types and numbers of the target population are able to investigate most of the societal structure, because this type only focuses on one type.

Systematic

A procedure to select the samples at specific periods or at an interval within the sampling time frame. For instance, choosing every ten samples or through a time interval (i.e. 30 minutes).

Since the main aim does not rely on timing interval examination, then this type is not suitable for the evaluation process.

Stratified Random

A refinement to random simple sampling; the target population is divided into separate strata or groupings on the basis of characteristic relevance to the research. The subsequent selection takes place from each stratum separately.

Useful in the selection of recipients because the questionnaires are being grouped according to the age and gender, in order to fulfil each group’s needs and requirements. In addition, to the interviewees, they are also grouped according to their positions in the Government bodies (i.e. Vice-ministers, governors, and local authorities’ chiefs).

Cluster

A multi-stage sample design; the target population is divided up into a large number of areas as in clusters of geographical adjacent cases. The data collection is either by choosing some clusters or by a large portion from each.

This type is not suitable, since it focuses on the respondents of the case study according to its area, but not considering the different respondents typology. It would be preferable to work on each case study in depth to understand all the users’ feedback rather than a general sample.

Multi- Stage

The selection process is repeated several times with different sampling units. The cases selected at an earlier stage making up the sampling frame for the next stage.

Since the selection process will take just one phase, then this type is not appropriate for the samplings’ selection.

B. Non-Probability Sampling (Unequal Selection Methods)

Quota

A technique in which interviewers are provided with a list of interlocking interviewee attributes, such as age and gender, which can be satisfied by selecting appropriate respondents.

Useful approach for selecting the respondents, according to the occupation, age, and sex but is not suitable for this study because there is no control over the number of participants and their group distribution.

Dimen- sional

An extension of quota sampling, in which various dimensions thought to be important, could be added to the selected criteria. For example, merging two separate dimensions and applying it through the sampling procedure.

Since it will give significant sophistication among the respondents’ selection procedure, it will be hard to justify the number of participants within a quarter in which the statistical census has changed and is not proper.

Convenience

A sample acquired with a minimum expenditure of resources, usually as part of a pilot study.

Useful approach for the pilot study phase, but will indeed has at least one respondent of each pre-selected stratified sample present.

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Purposive

A procedure in which the researcher’s judgement is too typical where a sample is built up that enables the researcher to satisfy specific needs in the study.

Useful approach for selecting external evaluators has been suggested to participate in the examination of policy implementation.

Snowball

A procedure based on a few early cases located by researchers and used as the sources of all the further cases in the sample.

Since no samples have been chosen before and the selecting procedure should only be focused on the current case studies to avoid any misinterpreted findings, therefore this type is not suitable for this study.

TABLE 3.2: TYPES OF SAMPLING TECHNIQUES AND THE SELECTION CLARIFICATION

(Samples type definition and data is adapted from Robson, 1993; Aldridge and Levine, 2001, and Vaus, 1991).

The samples chosen from the recipients/residents followed the ‘stratified random sampling technique’ by having various strata and a logical justification, as follows:

1. Merchants: Due to the high number of retail and commercial activities, it is useful to

investigate the main daily users among the ground floor users and acknowledge their feedback.

2. Male Residents: They are the main working force and those most affected by the

developments due to their continual interference.

3. Female Residents: They tend to have a different perspective to the male residents that

focuses on family needs, childcare and safety, and neighbour and social cohesion.

4. Young users/residents from the age of 18-28: As they are considered as the future users

and local workforce who will eventually have the right to interfere in the revitalisation process.

5. Elderly Residents: They are the connection with the past of and give how these quarters

used to look like and transformed during the last 30-40 years.

The other actors are selected by a ‘purposive sampling technique’ according to their occupational positions in the field of decision-making and implementation. The following table describes the classification of the different key players and the interviews held, interview dates and the number of participants either interviews or questionnaires.

49

Classification Specification Date of Interview

and Location Additional Comments

Objectives and Goals Initiators

State the basic objectives based on problemsolving agenda. Public Policy UNESCO UNDP AKTC Formal Decision- Makers

Formulate the Policies and Directives to achieve the objectives

stated.

2/A1 Cairo’s Governor

N/A

Difficult to conduct an interview due to personnel’s sensitive position.

2/A2 Cairo’s Vice Governor 2/B1 Ministry of Culture 2/B2 National Organisation for Urban Harmony (NOUH) CEO: Mr. Samir Gharib

12/01/2009

At the office of the participant.

2/C1 Ministry of Housing – Historic Cairo’s Revitalisation Centre

N/A

Difficult to conduct an Interview due to the shutdown of the centre.

Implementers

Put policies and directives into action.

3/B3 NOUH Heritage Department:

Prof. Salah Zaki Said

13/12/2008

At the private office of the participant.

3/B4 Research and Studies Dept. NOUH: Prof. S.O.

08/12/2008

At the office of the participant. 3/B5 Islamic Antiquities Department – Ministry of Culture N/A 3/B6 Supreme Council of Antiquities Officers and Engineers

07/12/2008 and other later visits.

At different sites and locations

A total of seven officers and engineers; were met during working hours at different sites. Intermediaries

Assist the implementers in the execution

process.

4/A Wasat District Local Authority Chief:

03/2009

At the office of the participant.

4/B NGO’s Presidents N/A

Two presidents have been contacted but refused to participate

(Developer) 4/C Prof. Mona Zakaria

02/02/2009

At the private office of the participant. Evaluators Evaluate the implementation process according to the objectives 5/E Academics:

-5/E1 Prof. Youhansen Eid Ain Shams University

25/01/2009 At the office of

the participant. -5/E2 Prof. Yehia Zeiny –

Helwan Uni. N/A

Failed to conduct an Interview

Recipients/ Residents

Users, merchants and residents.

- (6/1) Merchants and traders A total of 313 participants have

been included in the study covering

both case studies, and with different

numbers G am al ia Q ua rt er 60 D ar b A l A h m ar Q ua rt er 51 - (6/2) Male Residents 36 30 - (6/3) Female Residents 18 14 - (6/4) Young Users 51 43 - (6/5) Elderly Users (60>) 12 8

TABLE 3.3: DATA COLLECTION APPROACHES AND DATES IN RELATION TO THE KEY PLAYERS.

50

In the examination phase, there were 313 participants involved, the highest numbers of participants were the youth and male residents, but the least number of participants was the women residents due to the conservative culture which reduces the ability to meet with resident women freely. In general, the merchants were approached during their working hours at their shops along the streets. Most of them were welcoming and very helpful. As for the men, the researcher tend to approach them after the Friday prayers in front of mosques and sometimes at local cafes within the quarters, where they could be found them in groups which also helped in evoking deeper discussions; the same applied with the elderly who were approached at cafes. There were a low number of women residents participating due to the conservative culture and less freedom for women to enter into with discussions with strangers. Therefore, there was a need to have assistance from another female architectural colleague to approach some of the females at their homes. Furthermore, nine out of 14 interviews took place due to the difficulties encountered in approaching high officials due to their sensitive positions.