Development Studies Programme (DSP) - Exit poll : Palestinian legislative elections 2006

Exit Poll Fact Sheet

Sample and Methodology

Workshops

Meeting with International observation delegation

Activities in Photos

Important press release

Press releases

The press conference

Electoral law

Electoral System

Methodology

The poll results are based on interviews with a probability sample of voters

Sampling Frame

The sampling frame used is an electronic list of all the electoral stations in West Bank and Gaza Strip including Jerusalem Governorate. The sampling frame contains 2721 Electoral Stations and 1332408 electors.

Sampling
Three samples were designed as follows:

1. The National sample: a stratified cluster systematic random sample is selected on the national level; this sample is used to enable us to predict the winner group/groups. The sample consists of 2640 voters distributed over 191 electoral stations.

Sample Allocation:

The sample is allocated to strata (Governorates) using allocation proportionate to the total number of voters registered in each governorate

Sample Selection:

The National Sample is a multi-stage random sample. First, a stratified systematic random sample of 191 electoral stations is selected representing the 16 governorates in West Bank and Gaza Strip including Jerusalem Governorate. Electoral stations are selected with systematic random sampling and the sample allocation is done proportionate to the total number of registered voters in each governorate. Each voter in a governorate had the same chance to have his or her electoral station selected. Second, within each electoral station, voters are sampled systematically throughout the voting day at a fixed rate that gives all voters in an electoral station the same chance of being interviewed. This sample design is used to produce a self-weighted sample so as to be able to do data analysis and produce the main results in as short time as possible.

Stratification

Two levels of stratification are used to maximize the efficiency of the sample through capturing most of the variation exists in the study population, stratification variables used were: Locality Type (Urban, Rural, Refugee Camp), and Governorate (16 Governorates: 11 in West Bank and 5 in Gaza Strip)

Sample Size

Electoral Stations (ES) are used as primary sampling units (PSUs) where 191 (7 %) ES’s are selected out of the 2721 ES’s exist in the sampling frame, then from each ES voters are selected with systematic random sampling using fixed interval, hence the total sample size will not be determined before finishing the field work, however, an average of 13 voters are expected to be sampled per ES giving an expected total sample of 2650 voters.

2. Governorate samples: a systematic cluster random sample is selected from each governorate in order to enable us to predict the winner candidates in each governorate. The same electoral stations selected for the National Sample are included in the Governorate sample; in addition, an over sample of 15 stations is done in the small governorates because the proportionate allocation yielded a small number of electoral stations to be selected from these governorates..

Sample Allocation:

The same number of voters is selected from each governorate so as to get the same reliability of the statistics computed. In each Governorate a margin of error equal to 0.03 is used to compute the sample size.

Sample Size Calculation

The sample size was calculated based on the following assumptions:

The margin of error in estimating the population parameters will not exceed 2 percentage points on the national level and 3 percentage points on the Governorate level
The level of risk used for estimating the parameters is 5%
The design effect (Deff) equals 1.1
Most of the statistics calculated are proportions and percentages

The formula used to calculate the sample size is

Where

p: Is the proportion/percentage

Deff: Is the Design Effect

E: Is the margin of error

Table 1: Electoral Stations, Population and Sample Distributions by Governorate

GovCode	Governorate	Total Stations	National Sample	Governorate Sample	Characteristics Sample
1	Jenin	211	15	15	15
5	Tubas	40	3	7	3
10	Tul Karm	153	11	11	11
15	Nablus	259	18	18	18
20	Qalqelya	68	5	8	5
25	Salfit	54	4	7	4
30	Ramallah	226	16	16	16
35	Jericho	32	2	7	2
40	Annexed Jerusalem
41	Jerusalem J1	155	11	11	11
45	Bethlehem	144	10	10	10
50	Hebron	391	27	27	27
55	North Gaza	187	13	13	13
60	Gaza	332	23	23	23
65	Der El Balah	148	10	10	10
70	Khan Yunis	193	14	14	14
75	Rafah	128	9	9	9
	Total	2721	191	206	191

Table 2: Voters, Population and Sample Distributions by Governorate

GovCode	Governorate	Total Number	National Sample	Governorate Sample	Characteristics Sample
1	Jenin	101,664	202	595	101
5	Tubas	20,775	41	582	21
10	Tul Karm	73,340	145	594	73
15	Nablus	129,379	256	596	128
20	Qalqelya	33,713	67	588	33
25	Salfit	26,641	53	586	26
30	Ramallah	106,061	210	596	105
35	Jericho	16,073	32	577	16
40	Annexed Jerusalem		0		0
41	Jerusalem J1	48,340	96	592	48
45	Bethlehem	69,210	137	594	69
50	Hebron	186,054	369	597	184
55	North Gaza	98,535	195	595	98
60	Gaza	174,378	346	597	173
65	Der El Balah	79,051	157	594	78
70	Khan Yunis	103,377	205	595	102
75	Rafah	65,817	130	593	65
	Total	1,332,408	2641	9472	1321

Sample Weighting
No weighting is needed to reflect the probability of selection since the sample is a self-weighted one. However, if a significant non response occurred then there will be a need for weighting to adjust for the possible bias resulted from voters who were missed or refused to be interviewed, this weighting adjustment will be based on their observed age, and sex.

Sample Plan (to be used by the Field Work Supervisors and Interviewers)

From each selected (assigned) electoral station select, randomly, the voters by the following procedure:

Start working in the electoral station by the time the voting process starts there
Read the random number r assigned to your electoral station (say r = 5)
Start counting the voters as they exit the electoral station (count 1, 2, ..., r)
Select the voter with the number corresponding to the random number chosen r (5 in the example). And make the interview with him/her.
Use the sample control form that you carry and make a circle around the voter serial number.
The form tells you the number of different questionnaires needed to be filled for the selected voter; you might fill 1, 2, or 3 different questionnaires for each selected voter.
Then start counting again from 1 until you reach the sampling interval assigned to the electoral station then make the interview with voter number corresponding to the sampling interval number, and start counting again from 1 to the sampling interval in each time and so on until you finish the number of questionnaires assigned to that electoral station or until the voting process ends in the assigned electoral station.
If a selected voter refused or couldn’t participate, fill a questionnaire for him/her and write down in his/her questionnaire at least the following information:

a) Interview result (refused, missed,)

b) His/her sex

c) His/her age group (as you observe it).

Under any circumstances, do not replace the voter who refused to participate, because that might alter the age/sex distribution of the sample
Make sure to assign a questionnaire for non-respondents (refusals,) because that will help the data analysis staff to re-weight the sample to adjust for non-response.
Do not change the assigned selection interval.
The sample should spread over the whole Election Day.

Do not replace the selected person if you do not like him/her
Remember; we do not intend to make the sample representative of the location, all what we intend to do is to make the total sample representative of the total population and this could be achieved if we stick to the sample plan

Table 1: Electoral Stations, Population and Sample Distributions by Governorate

GovCode	Governorate	Total Stations	National Sample	Governorate Sample	Characteristics Sample
1	Jenin	211	15	15	15
5	Tubas	40	3	7	3
10	Tul Karm	153	11	11	11
15	Nablus	259	18	18	18
20	Qalqelya	68	5	8	5
25	Salfit	54	4	7	4
30	Ramallah	226	16	16	16
35	Jericho	32	2	7	2
40	Annexed Jerusalem
41	Jerusalem J1	155	11	11	11
45	Bethlehem	144	10	10	10
50	Hebron	391	27	27	27
55	North Gaza	187	13	13	13
60	Gaza	332	23	23	23
65	Der El Balah	148	10	10	10
70	Khan Yunis	193	14	14	14
75	Rafah	128	9	9	9
	Total	2721	191	206	191

Table 2: Voters, Population and Sample Distributions by Governorate

GovCode	Governorate	Total Number	National Sample	Governorate Sample	Characteristics Sample
1	Jenin	101,664	202	595	101
5	Tubas	20,775	41	582	21
10	Tul Karm	73,340	145	594	73
15	Nablus	129,379	256	596	128
20	Qalqelya	33,713	67	588	33
25	Salfit	26,641	53	586	26
30	Ramallah	106,061	210	596	105
35	Jericho	16,073	32	577	16
40	Annexed Jerusalem		0		0
41	Jerusalem J1	48,340	96	592	48
45	Bethlehem	69,210	137	594	69
50	Hebron	186,054	369	597	184
55	North Gaza	98,535	195	595	98
60	Gaza	174,378	346	597	173
65	Der El Balah	79,051	157	594	78
70	Khan Yunis	103,377	205	595	102
75	Rafah	65,817	130	593	65
	Total	1,332,408	2641	9472	1321

The Sampling Control Forms

These forms are intended to be used by the fieldworker to help hem/her select the sample of voters for each of the three different samples in a way that is consistent with the sample design.

It is very important to use these forms

There is one form for each governorate and all electoral stations in the same governorate have the same form

The first column (gov-sample) shows the serial number of the selected voter in the governorate sample and it shows how many voters are needed from each electoral station, this number is fixed in each governorate , for example it is 40 voters in Jenin stations and 83 in Tubas stations,… and so on.

Give each questionnaire a serial number which starts from 1 and ends in this number (ex: ends with 40 in Jenin Stations)

The second column (Nat. Samp) gives the selected voter number who is going to be interviewed also for the national sample

The third column (Char. sam) gives the selected voter number who is going to be interviewed also for the voter characteristic sample

Sample Control form ---- Jenin

gov-sample	Nat-samp	Char-sam	gov-sample	Nat-samp	Char-sam
1	1	1	26
2			27
3			28	28
4	4		29
5			30
6			31	31	31
7	7	7	32
8			33
9			34	34
10	10		35
11			36
12			37	37	37
13	13	13	38
14			39
15			40	40
16	16
17
18
19	19	19
20
21
22	22
23
24
25	25	25

Sample Control form ---- Tubasطوباس

gov-sample	Nat-samp	Char-sam	gov-sample	Nat-samp	Char-sam
1	1	1	26
2			27
3			28
4			29
5			30
6			31	31
7	7		32
8			33
9			34
10			35
11			36
12			37	37	37
13	13	13	38
14			39
15			40
16			41
17			42
18			43	43
19	19		44
20			45
21			46
22			47
23			48
24			49	49	49
25	25	25	50

Sample Control form ---- Tubasطوباس

gov-sample	Nat-samp	Char-sam	gov-sample	Nat-samp	Char-sam
51			76
52			77
53			78
54			79	79
55	55		80
56			81
57			82
58			83
59
60
61	61	61
62
63
64
65
66
67	67
68
69
70
71
72
73	73	73
74
75

Sample Control form ---- Tulkarm طولكرم

gov-sample	Nat-samp	Char-sam	gov-sample	Nat-samp	Char-sam
1	1	1	26
2			27
3			28
4			29	29
5	5		30
6			31
7			32
8			33	33	33
9	9	9	34
10			35
11			36
12			37	37
13	13		38
14			39
15			40
16			41	42	41
17	17	17	42
18			43
19			44
20			45	45
21	21		46
22			47
23			48
24			49	49	49
25	25	25	50

Sample Control form ---- Tulkarm طولكرم

gov-sample	Nat-samp	Char-sam	gov-sample	Nat-samp	Char-sam
51			53	53
52			54

Sample Control form ---- Nablus

gov-sample	Nat-samp	Char-sam	gov-sample	Nat-samp	Char-sam
1	1	1	26	26
2			27
3	3		28	28	28
4			29
5	5	5	30
6			31	31
7			32
8	8		33	33	33
9
10	10	10
11
12	12
13
14
15	15	15
16
17	17
18
19	19	19
20
21
22	22
23
24	24	24
25

Sample Control form ---- Qalqelya

gov-sample	Nat-samp	Char-sam	gov-sample	Nat-samp	Char-sam
1	1	1	26
2			27
3			28	28
4			29
5			30
6	6		31
7			32
8			33
9			34	34	34
10			35
11			36
12	12	12	37
13			38
14			39	39
15			40
16			41
17	17		42
18			43
19			44
20			45	45	45
21			46
22			47
23	23	23	48
24			49
25			50	50

Sample Control form ---- Qalqelya

gov-sample	Nat-samp	Char-sam	gov-sample	Nat-samp	Char-sam
51
52
53
54
55
56	56	56
57
58
59
60
61	61
62
63
64
65
66
67	67	67
68
69
70
71
72	72
73
74

Sample Control form ---- Salfeet

gov-sample	Nat-samp	Char-sam	gov-sample	Nat-samp	Char-sam
1	1	1	26	26	26
2			27
3			28
4			29
5			30
6			31
7	7		32	32
8			33
9			34
10			35
11			36
12			37
13	13	13	38
14			39	39	39
15			40
16			41
17			42
18			43
19			44
20	20		45	45
21			46
22			47
23			48
24			49
25			50

Sample Control form ---- Salfeet

gov-sample	Nat-samp	Char-sam	gov-sample	Nat-samp	Char-sam
51	51	51	76
52			77	77	77
53			78
54			79
55			80
56			81
57			82
58	58		83	83
59			84
60
61
62
63
64	64	64
65
66
67
68
69
70
71	71
72
73
74
75

Sample Control form ---- Jericho

gov-sample	Nat-samp	Char-sam	gov-sample	Nat-samp	Char-sam
1	1	1	26
2			27
3			28	28
4			29
5			30
6	6		31
7			32
8			33
9			34	34	34
10			35
11			36
12	12	12	37
13			38
14			39	39
15			40
16			41
17	17		42
18			43
19			44
20			45	45	45
21			46
22			47
23	23	23	48
24			49
25			50	50

Sample Control form ---- Jericho

gov-sample	Nat-samp	Char-sam	gov-sample	Nat-samp	Char-sam
51			76
52			77	77	77
53			78
54			79
55			80
56	56	56	81
57			82	82
58
59
60
61	61
62
63
64
65
66
67	67	67
68
69
70
71
72	72
73
74
51

Sample Control form ---- Ramallah

gov-sample	Nat-samp	Char-sam	gov-sample	Nat-samp	Char-sam
1	1	1	26	26
2			27
3	3		28	28	28
4			29
5			30
6	6	6	31	31
7			32
8			33
9	9		34	34	34
10			35
11			36
12	12	12	37	37