5. Evaluation

Verification in a data linkage project involves:

• Ensuring alignment of methods and processes with project specifications

• Conducting code reviews and unit testing

• Confirming the robustness of the chosen methodology through expert review

• Clearly documenting any deviations from requirements

Validation in a data linkage project entails:

• Sense checking, comparing results against established truths or manual inspections to verify plausibility with users and data linkage experts.

🔴 RED:
Insufficient practices in verification, validity checks. No established routine for sense checking or peer reviews in data linkage projects.

🟡 AMBER:
Intermittent verification and validity checks with some inconsistencies, along with occasional sense checking and peer reviews that may lack consistency.

🟢 GREEN:
Verification and validity checks performed. Clear practices and established routines for sense checking and thorough peer reviews.

Record-level checks

• Identifying errors in specific records

• Analysing metadata like matching steps and confidence scores

Aggregate-level checks

• Identifying agreement patterns in linking variables

• Identifying biases

• Assessing analytical outcomes' sensitivity to parameter adjustments (if data permits)

• Cross-referencing outcomes with alternative sources or linkage methods

Other checks

• Utilising clerical resources (if available) for structured reviews to establish a ground truth

• Computing precision, recall, and F1-score (if a ground truth is established)

🔴 RED:
The results of the Data Linkage process have not been evaluated. The impact of the linked data quality is unknown on subsequent procedures.

🟡 AMBER:
Partial evaluation of the linked data is available but it inconsistent.

🟢 GREEN:
A process to evaluate the data linkage quality is in place and is comprehensive. Users of linked data are aware of the outcomes of this evaluation.

• Track processing speed and identify bottlenecks for improvement

• Tackle factors like dataset size, hardware limitations, and inefficient algorithms

• Ensure your process can handle larger datasets and increased frequency without sacrificing quality

🔴 RED:
The linkage process speed has not been assessed. No attempts to improve speed have been made.

🟡 AMBER:
Some efforts are made to improve the efficiency of the linkage but partially or not implemented.

🟢 GREEN:
Efficient data linkage processes have been achieved through proactive reviews and enhancements.

• The size of the datasets being linked influences the computational resources - as larger data sets require more processing power and time, memory, and storage.

• Allocate sufficient computational resources for diverse types of DL projects and optimise processing times to ensure efficient data linkage.

🔴 RED:
Insufficient computational resources which forces the use of suboptimal linkage methods.

🟡 AMBER:
There is allocation of resources, but it is not ideal for complex data linkage projects.

🟢 GREEN:
Adequate allocation of computational resources for different types of DL projects to minimise the linkage error.

Function to measure the run time of a function

import timeit
import time

def measure_function_time(f):
    '''
    Times how long a function takes to run in seconds
    '''

    start_time = timeit.default_timer()
    f()
    end_time = timeit.default_timer()
    print(f"It took {end_time-start_time}s to call the function")


def wait_15_seconds():
    '''
    Function called to wait 15 seconds before executing print statement
    '''
    time.sleep(15)
    print('Waited 15 seconds!')

measure_function_time(wait_15_seconds)

Waited 15 seconds!
It took 15.000131200999988s to call the function

Understanding how long a function takes to run can be used to understand resource allocation in your machine, and can be used as a proxy to understand the load in different parts of the data linkage process.

Function to measure CPU usage

import psutil

def get_cpu_usage(time_period):
    '''
    Prints the CPU usage over a time period
    '''

    cpu_usage = psutil.cpu_percent(time_period)
    return cpu_usage

time_period = 10

print('The CPU usage for the last',time_period,'seconds is : ',get_cpu_usage(time_period))

The CPU usage for the last 10 seconds is :  0.4

Understanding how CPU is being used helps understand resource allocation in your machine, and can be used as a proxy to understand the load of different data linkage models

Function to measure the ram memory being used

import psutil

def get_ram_memory():
    '''
    Returns the % of RAM being used, and number of GB being used by RAM at a moment in time
    '''

    ram_percentage_used = psutil.virtual_memory()[2]
    ram_gb_used = psutil.virtual_memory()[3]/1000000000
    return ram_percentage_used, ram_gb_used


print(get_ram_memory())

(6.9, 0.774934528)

Understanding how RAM is being used helps understand resource allocation in your machine, and can be used as a proxy to understand the load of different data linkage models