A Promise in the Name of God

To preserve the integrity of the experiment, the intervention will remain concealed until the study is completed.

The experiment involves two interventions:

First, for each seller-day session (morning or afternoon), we randomize whether sellers are instructed to refrain from using religious oaths during their conversations with customers. In the control sessions, no such instruction is given.

Second, for each seller-day session, we randomize whether a poster is displayed on the street where the seller is located. The poster displays part of a verse from the Qur’an:

> “Allah will not take you to account for a slip in your oaths. But He will take you to account for the oaths which you solemnly swear...”
> — Qur’an 5:89

In contrast, no such poster is displayed in the control sessions. The explanation of this verse, as by Dr. Mohammad Mahmud Ghali in the Towards Understanding the Ever-Glorious Qur’an book, is as follows:

> “Allah does not take you to task for an idleness in your oaths, but He takes you to task for whatever contracts you have made by oaths. So the expiation thereof is the feeding of ten indigent persons with the average of that wherewith you feed your own families; or their raiment; or the freeing of a neck (i.e., a slave). Yet, for him who does not find the means, then (the expiation is) the fasting for three days. That is the expiation of your oaths when you have sworn; and keep your oaths. Thus Allah makes evident to you His signs, that possibly you would thank (Him).”

2025-06-01

2025-08-01

Sales volume (measured in 100-gram units for items sold in bulk, and in number of packages for items sold in factory-packaged format)

For each seller-day-session—that is, each seller-day-morning or seller-day-afternoon—we record the quantity sold for each of the five items. Since sellers offer five distinct products, each session yields five separate sales volume observations.

To preserve the integrity of the experiment, the experimental design will remain concealed until the study is completed.

To evaluate the effectiveness of religious oaths on sales rates, we recruit a team of professional sellers who have at least some experience as street vendors in the country and operate handcarts to sell goods on a daily basis. This type of selling is common in the country and does not require a license.

Each seller offers five items from their handcarts: black tea, candy, pasta, dates, and turmeric. These items are selected for their non-perishable nature and widespread availability in local markets. They are sold in two formats: factory-packaged and loose (unpackaged). Factory-packaged items are sold in sealed packages, as typically seen in developed markets, while loose items are displayed in food-grade storage containers.

To ensure consistency and quality, we source the goods in bulk from high-quality suppliers. This approach guarantees that consumers receive premium-quality goods, minimizing any variation in quality that could affect the experiment.

For a given seller-day—which consists of two sessions (morning and afternoon)—the format of all five items is randomized. That is, all items are either factory-packaged or loose (unpackaged in food-grade containers). For logistical reasons, we are unable to randomize the format separately within seller-day sessions.

1. Factory-packaged
2. Loose (unpackaged in food-grade storage containers)

We compiled a list of neighborhoods in Kabul where mobile vendors are commonly found. Each day, sellers position their carts at a location of their choice within a neighborhood that we randomly select. Sellers are recruited for approximately six weeks. For each seller, the working day consists of morning hours (8:00 AM to 12:00 PM) and afternoon hours (2:00 PM to 6:00 PM). During the midday break (12:00 PM to 2:00 PM), sellers rest and have lunch. In the afternoon, sellers relocate their carts to a nearby street of their choice within the same neighborhood.

Each seller is provided with the goods for free, all in the randomly assigned format. That is, all five items are either factory-packaged or loose (unpackaged in food-grade containers). We supply the goods, set the prices, and collect the revenue from sales.

Sellers receive the following compensation: regardless of how much a seller sells during the approximately six-week experiment, each receives AFN 10,000 (approximately USD 140) per month. In addition, each seller earns 5 percent of the total value of their sales. The variable, commission-based component is intended to incentivize effort.

Item prices are set at the median of at least five price quotes from local stores for the corresponding format (factory-packaged or loose). This pricing strategy ensures consistency with local market conditions and reflects standard consumer expectations. At the end of each session (morning and afternoon), we record the quantity of each item sold and collect the revenue.

It is worth noting that the results from this experiment will be complemented by analysis of hundreds of hours of trade negotiations recorded by our research assistants, as well as by large-scale taste-testing surveys we conducted. We do not discuss these components of the research project here, as they do not involve experimental interventions and are survey-based in nature.

Randomization is done by a computer.

seller-day-session

Yes

We have recruited 26 sellers.

9360 Sale Volume (26 sellers*36 days*2 sessions*5 items)

The experiment includes two interventions at each seller-day-session. At a given seller-day-session, the seller is randomly instructed to refrain from using religious oaths during their interactions with customers. Additionally, we randomize whether a poster is displayed on the street where the seller is located during that session. Therefore, we expect to have 2,340 sales volume observations in each of the four treatment arms:

1. No instruction, no poster
2. No instruction, poster displayed
3. Instruction to refrain from oaths, no poster
4. Instruction to refrain from oaths, poster displayed