Table 2 Sampling method used by included studies

Bogale et al., 2019 [25]

Multistage sampling was used. Two subcities were randomly chosen. Then, four districts were proportionally selected from the chosen subcities using simple random sampling. Subsequently, 605 households were proportionally selected from the identified districts using systematic sampling methods based on a predetermined Kth value. Interviews were conducted with every Kth household, with the initial household chosen randomly.

Throughout the data collection phase, house numbers served as the sampling frames. If a household declined participation, the next household in the sequence was approached. Interviews were conducted with heads of households until the final sample size was achieved. The study instruments were derived from a review of existing literature and previous studies.

Erku et al., 2017 [26]

The selection of households within administrative areas (kebeles) employed a multistage stratified random sampling technique. Initially, five administrative areas were randomly chosen to ensure a representative sample. The number of households to be interviewed in each administrative area was determined proportionally according to the total number of households in each kebele. Subsequently, a systematic random sampling method was utilized to select study participants within these areas. In cases where more than one eligible respondent was found within a selected household, a respondent was chosen through a lottery method.

The questionnaire used in the study was developed by modifying items from a previously employed instrument. The items were meticulously reviewed for relevance by a team of experts, including experienced clinical pharmacists and public health professionals.

Eticha et al., 2014 [27]

The selection of departments involved a stratified sampling technique. Three departments were selected, and then further stratified based on study year. Respondents from each study year were selected proportionally according to their population size, utilizing simple random sampling techniques. The structured questionnaire was developed through a comprehensive review of relevant literature and previously standardized instruments.

Gebeyehu et al.,

2015 [28]

The sampling methodology involved a multistage stratified random sampling approach to select households in both rural and urban kebeles. To ensure representation, three urban and three rural kebeles were randomly selected using a simple random sampling technique. Within these selected kebeles, a systematic random sampling technique was employed to choose study participants. Data collection utilized a pre-tested and structured questionnaire to gather relevant information.

Gebrekirstos et al.,

2017 [29]

Samples districts were chosen using a simple random sampling technique. Drug retail outlets samples were selected randomly. Proportional to sample size technique was used to determine the number of outlets selected. Subsequently, study participants were recruited using consecutive sampling technique. A pre-test and structured questionnaire was employed to gather relevant data.

Kassa et al., 2022 [30]

The study employed a multi-stage sampling technique. Samples were selected using a lottery method. The sampling frame was taken from human resource department. The number of HCPs to be included from each hospital was determined proportionally based on the size of the staff. Following this, HCPs were stratified into physicians, nurses, and pharmacy professionals, and the final sample size was allocated proportionally according to the respective number of HCPs from each department in each hospital. Convenient sampling method was then utilized to select the final sampling units. The data collection tool was prepared after reviewing previous studies on the same issue.

Ayana et al., 2021 [31]

A simple random sampling technique was utilized to samples. Subsequently, the history of antibiotic purchasers was assessed for each selected pharmacy and drug store. Based on this historical data, systematic random sampling methods were employed to select study participants from each establishment. Every third purchaser was selected based on their sequence of visiting the drug retail outlet, with the initial study subject determined randomly through a lottery method. The sample size was allocated proportionally to each pharmacy or drug store.

The questionnaire used for data collection was prepared from previous studies. Exit interviews were conducted immediately after a person purchased antibiotics, with their consent, at the pharmacies or drug stores.

Demissie et al., 2022 [32]

The selection of sample households relied on the frame comprising three kebeles, along with their respective household numbers, obtained from the kebele administration offices. Proportional probability to size sampling was employed to allocate a proportional sample size for each kebele. Subsequently, a systematic sampling technique was applied, determining the interval by dividing the total number of households in in the study area by the final sample size. Then, every Kth household whose members voluntarily participated was interviewed based on their sequence of house numbers.

In cases where two or more eligible respondents were present in the same household, only one of them was randomly selected and included in the study. Face-to-face interviews were conducted with eligible respondents using structured, pre-tested questionnaires in selected households where occupants were available during data collection.

Simegn & Moges, 2022 [33]

The study employed a stratified sampling technique to proportionally allocate households to each kebele administration. Within the city, five kebeles and three rural kebeles were selected using a lottery method. The number of households was obtained from the City administration, and lists of households with their respective addresses were acquired from each kebele administrative office.

From each stratum, samples were drawn proportionally to their size using the number of households as the sampling frame. Household selection within urban and rural kebeles was conducted using a systematic random sampling technique. The sampling interval for each kebele was determined by dividing the total number of households by its proportionally allocated sample size. Subsequently, every Kth household was interviewed, with the first household selected through a lottery method.

Data collection utilized a semi-structured, pretested questionnaire adapted from previous studies. Interviews were conducted with the head of the household or a member designated as the next head or responsible person of the household.

Dache et al., 2021 [34]

A multistage sampling approach was utilized to categorize study subjects. Initially, four kebeles were randomly selected from the six kebeles in the town. Subsequently, the number of households to be selected from each chosen kebele was proportionally allocated based on the total number of households in that kebele. Lists of households were obtained from each kebele health post, and a sampling frame was independently developed for each selected kebele based on census results.

The calculated sample size was then proportionally allocated to all selected kebeles based on their respective number of eligible households. Study subjects were selected using a simple random sampling procedure. A door-to-door interview approach was employed for each kebele to identify suitable study participants until the requested sample size was attained. In instances where there were two or more eligible households, a chance method was used to select one of them.

The questionnaire used for data collection was prepared by modifying related literature to ensure alignment with the study objectives and conceptual framework. Data were collected using interviewer-administered structured and pretested questionnaires.

Mossa et al., 2012 [35]

The sampling procedure involved randomly selecting a sample of adult individuals from the town using a multi-stage stratified clustered sampling technique. Initially, residential areas within the town were randomly selected. From these areas, sample households were randomly chosen. Subsequently, one individual from each household was interviewed.

To collect information, a structured and pre-tested questionnaire was utilized. The validity of the questionnaire was assessed through in-depth discussions.