Study design
This study used a cross-sectional study design, and was conducted among female secondary school students (of forms two, three, and four aged 12–21 years) in Dar es Salaam. This study aimed to determine the magnitude of knowledge and attitudes regarding FP methods and use of these methods among female secondary school students.
Study setting
Dar es Salaam is the largest city in Tanzania. It serves as the main administrative center and economic hub for the country, and is located in the Coastal Zone along the Indian Ocean The population of Dar es Salaam exceeds 4 million people, and the city has a large adolescent population who are sexually active. The city is subdivided into five districts: Ubungo, Kinondoni, Temeke, Kigamboni, and Ilala municipalities. The study site was a girls-only secondary school admitting both day and boarding students; it is located in Ilala district, Upanga West. The school has 240 students aged 12–21 years from all five districts of Dar es Salaam City.
Inclusion and exclusion criteria
The inclusion criteria were students aged 12–21 years, willing to participate in this study, and able to communicate in English or Swahili. Students that did not meet these criteria were excluded.
Sampling method
A multi-stage sampling method was used to select eligible participants. Ilala district was selected in the first stage. One girls-only school from among the schools in Ilala district was selected in the second stage, with students aged 12–21 years invited to participate in this study. This sampling method was considered the best way to include all subjects that met the researchers’ criteria (14), which in this case was girls from girls-only secondary schools in Ilala district.
Sample size calculation
The sample size was calculated using the Leslie Kish sample size formula. According to (15) it is essential to use the correct sample size to accurately represent the population. Therefore, the percentage of the total population used for the sample size in this study was 34%. The sample size was calculated using the formula as follows.
N = Z2P (100 − P)/E2
N = estimated sample size, P = expected population, E = margin of error, Z = level of significance, where Z is 1.96 = 95% (16)
N = (1.96)2 X 10.7 (100 − 10.7) = 146.7
(5)2
Data collection
Data were collected using a structured self-administered questionnaire that covered demographic information and knowledge about, attitudes toward, and use of FP. The tool was developed by the present researchers, and questions were formulated based on knowledge of sexual and reproductive health. Experts in sexual and reproductive health were consulted for their input. A pilot study was conducted with 20 students from a secondary school for girls in Dar es Salaam. These participants were randomly selected and had the same characteristics as the study group. This facilitated our understanding of the feasibility of the study instrument. These participants were excluded during the actual data collection to avoid contamination of the study sample. The results of the pilot study were used to modify the content of the questionnaire.
Data collection procedure
The questionnaire was distributed to study participants. After providing informed consent, participants were required to respond to questions covering demographic information and their knowledge, attitudes, and use of FP methods. The questionnaire was completed at school in a classroom and it took about 30 minutes.
Outcome measures
FP method was regarded as the dependent variable. The independent variables were age, education, knowledge of FP methods, use of FP, and attitude toward FP. Students that responded correctly to questions regarding functions and types of FP methods were considered to have adequate knowledge, whereas those with incorrect responses were regarded as having inadequate knowledge. With regard to attitude, participants were asked: “Would you advise your peers to use family planning” (“yes” or “no”). Those who responded “yes” were considered to have a positive attitude toward FP methods.
Data analysis
Data analysis was performed using SPSS version 20.0 (Armonk, NY: IBM Corp.). Descriptive and inferential statistics were calculated. The frequencies of study variables were computed and represented as numbers and percentages. Further analyses using Pearson’s chi-square tests were used to determine associations between categorical variables.