Mop-Up Operations

Mop-up operations are critical for achieving target response rates and minimizing differential attrition. This guide covers systematic identification of difficult-to-reach respondents, specialized team deployment, intensive field strategies, and cost-effectiveness monitoring.

Key Takeaways

Mop-up operations protect research validity by achieving target response rates and minimizing differential attrition between study groups.
Budget proactively: Allocate 15-25% of field budget before initial fieldwork ends—studies without planning achieve lower response rates.
Systematically identify and assign cases by difficulty level to maximize completion rates with specialized enumerators.
Monitor cost-effectiveness to determine when to continue or conclude operations.

Purpose and Timing

Mop-up operations serve as a critical final phase of data collection, targeting respondents who were not successfully interviewed during the initial fieldwork period. These operations apply to both single-round and multi-round studies.

Purpose

Mop-up operations achieve multiple critical objectives that protect data quality and research validity:

Interview difficult-to-reach respondents identified during initial tracking
Recover temporarily unavailable respondents
Meet target sample size and response rate goals
Minimize differential attrition between study groups
Maximize return on research investment

When to Conduct Mop-Up?

After completing first round of survey visits in each area
When response rate falls below target threshold
Before final deadline for data collection
When substantial number of cases remain after initial attempts
When budget allows for additional field time

Budget Requirements

Successful mop-up operations require substantial upfront planning and dedicated financial resources that differ from regular fieldwork costs:

Allocate 15-25% of field budget specifically for mop-up
Higher transportation costs (longer distances to scattered respondents)
Specialized tracking team with high skill level
Consider incentive or informant compensation costs
Plan for extended timeline beyond initial field period

Budget and Schedule Mop-Up in Advance

Do not treat mop-up as an afterthought.
Budget money and schedule time for mop-up BEFORE initial fieldwork ends.
Enumerators need dedicated time to find respondents after unsuccessful initial attempts.
Studies that don’t plan for mop-up typically achieve lower response rates and higher attrition.

Systematic Approach

Successful mop-up begins with systematic identification and prioritization of remaining respondents using tracking data collected throughout initial fieldwork.

Identification Process

Cross-referencing the master sample list with completed surveys to generate a dataset of non-completed cases
Categorizing cases by tracking difficulty based on the number and outcomes of previous contact attempts
Dividing cases into easy (few attempts), medium (several attempts), and hard (many attempts or complex situations)
Using real-time data platforms, scripted summaries, and interactive dashboards to provide immediate visibility into case status and tracking patterns

Strategic Assignment

After categorizing cases by difficulty, assign them strategically to maximize completion rates:

Assign the most experienced enumerators to the most challenging cases while ensuring simpler cases receive attention first
Balance workload distribution by giving each enumerator a mix of easy, medium, and hard cases to maintain productivity
Prioritize cases that address differential attrition between study groups
Consider geographic clustering to minimize travel costs for scattered respondents
Monitor progress and reassign cases if new information changes difficulty assessment

IPA Data Management System Approach

This approach uses IPA’s Data Management System to identify non-completed cases and categorize them by tracking difficulty.

* Generate dataset of respondents not yet interviewed
progreport using "${data}/master_sample.dta", ///
    id(respondent_id) ///
    masterid(respondent_id) ///
    surveydata("${data}/completed_surveys.dta") ///
    notfound /// Option outputs only non-completed cases
    save("${data}/mopup_list.dta")

* Categorize by tracking difficulty
use "${data}/mopup_list.dta", clear
merge 1:m respondent_id using "${data}/tracking_attempts.dta"

* Count attempts per respondent
bysort respondent_id: gen attempts = _N

* Categorize difficulty
gen difficulty = "Easy" if attempts <= 2
replace difficulty = "Medium" if attempts > 2 & attempts <= 5  
replace difficulty = "Hard" if attempts > 5 & !missing(attempts)
replace difficulty = "No attempts" if missing(attempts)

* Save prioritized list
save "${data}/mopup_prioritized.dta", replace

See more in IPA’s Data Management System

SurveyCTO Case Management Approach

This approach leverages SurveyCTO’s built-in case management features for real-time tracking and automatic updates.

Filter cases by status (not started, in progress, specific outcome codes)
Export case list with current information
Assign cases to specialized mop-up enumerators
Track progress in real-time as cases are completed
Automatic updates when surveys uploaded (requires internet)

Advantages of Case Management:

Real-time updates eliminate manual list management
Prevents duplicates (completed cases auto removed)
Efficient reallocation between enumerators
Transparent progress for all team members

See more in SurveyCTO guide to case management

Specialized Mop-Up Teams

Mop-up operations often benefit from dedicated enumerators with specific skills.

Team Composition	Desirable Skills
• 2-4 highly skilled enumerators • Strong rapport-building abilities • Persistence and creative problem-solving • Familiarity with all survey regions • Experience with difficult tracking scenarios	• Knowledge of local languages and dialects • Connections in multiple communities • Comfort with long-distance travel • Ability to work independently • Adaptability to unusual situations

Team Support

Dedicated field coordinator for mop-up phase
Higher daily compensation reflecting difficulty
Adequate transportation budget
Communication allowance
Flexibility in schedule and approach

Quote from IPA Field Coordinator

“Tracking requires patience, a great deal of energy for back and forth movements, respondent’s information management, etc. Enumerator has to be detail-oriented about the pieces of information coming in on a particular respondent, and must exercise good skill of rapport building.”

Mop-Up Strategies and Tactics

Intensive Effort Examples

Travel to distant locations (other regions, countries if applicable)
Overnight stays near respondent’s location for early morning contact
Persistent monitoring of expected return dates
Coordination with field teams across multiple locations
Use of all information, even vague or uncertain leads

Timing Optimization

Early morning visits before respondents leave for work
Consideration of respondent’s economic activities (market days, business hours)
Scheduling around local events (religious services, community meetings)
Multiple visits at different times of day/week

Information Utilization

Follow up on all leads, however incomplete
Chain together partial information from multiple sources
Ask new questions based on previous responses
Use even vague information (“sometimes seen near…”)

Applying Longitudinal Strategies in Mop-Up

Many strategies described in Longitudinal Tracking are valuable during mop-up:

Snowballing: Show photobook to successful respondents to locate difficult cases
Community contacts: Revisit key informants with specific difficult cases
Phone banking: Intensive calling for specific hard-to-reach respondents
Project visibility: Community members may remember seeing difficult cases

The difference: In longitudinal tracking, these are proactive strategies applied to entire sample. In mop-up, they are intensive tactics focused on specific difficult cases.

Incentives During Mop-Up

Consider offering incentives for hard-to-reach respondents
May introduce new incentive structures during mop-up phase
Balance incentive level with budget constraints
Document any differential incentives for bias assessment

Monitoring and Decision-Making

Successful mop-up operations require continuous monitoring of progress and cost-effectiveness to determine when to continue efforts or conclude the operation.

Key Metrics During Mop-Up

Metric	Target	Action if Below Target
Daily completions	2-5 per enumerator	Reassess difficulty of assigned cases
Attempt-to-completion ratio	< 4:1	Improve information quality or targeting
Cost per completed survey	Budget-dependent	Consider phone interviews for distant respondents
New information per attempt	> 50%	Train team on probing and information gathering
Weekly response rate gain	+2-5%	Evaluate if continuing is cost-effective

Decision Points

When to Continue Mop-Up

Steady progress toward response rate goals
New information being gathered on difficult cases
Budget remains available
Differential attrition between groups remains acceptable
Team morale and effectiveness maintained

When to Conclude Mop-Up

Diminishing returns (no new completions despite attempts)
Budget exhausted
Timeline constraints reached
Acceptable response rate achieved
Further efforts unlikely to change key results
Systematic barriers prevent access to remaining cases

Documentation Requirements

For field reports and methodological transparency, record:

Dates of mop-up operations: Start and end dates
Team composition: Number and names of mop-up enumerators
Respondents targeted: Total number and characteristics
Successful interviews: Number completed during mop-up phase
Strategies employed: Methods that proved most/least effective
Costs incurred: Budget spent on mop-up activities
Remaining non-response: Final count and reasons for non-completion
Differential patterns: Whether mop-up success differed by study group