Quality control uses end-of-line inspections to check for defects, but this approach makes it difficult to achieve high quality levels. Poka yoke, or mistake-proofing, takes a different approach by controlling processes to prevent defects from occurring. This is done through mechanisms that catch errors immediately and require successive checks. Quality assurance takes a "beginning-of-line" approach by establishing procedures upfront to ensure good quality from the start. It involves meeting standards like ISO 9001, which defines quality management system requirements and is widely used internationally. Both quality control and assurance aim to improve product and service quality.

1. Approaches in Ensuring Quality
A. Quality Control
 Used in the military in 1950s & 1960s
 “end of line” strategy (inspection done at the end)
 Drawback: 99% quality is difficult to achieve thru inspection. In the service sector, 99.9
% quality is unacceptable
Ex: 1/1000 days of poisoned tap water?
1/1000 planes missing the runway?
1/1000 babies dropped in the maternity ward?
 Other services require 100 % perfect or error-free.
(An Impossible Dream but an Absolute Necessity)
Shigeo Shingo’s poka yoke principle: “Control must be on the process to ensure that faults
cannot be produced.”
 feedback immediately after errors are made
 items produced must be checked successively, self-check, or inspected at the
source.
‘Poka yoke’ is a Japanese term, w/c means “mistake proofing”.
 anymechanism in a lean manufacturing process that helps an equipment operator avoid
(yokeru) mistakes (poka).
 Its purpose is to eliminate product defects by preventing, correcting, or drawing attention
to human errors as they
occur.
 Poka yoke, was adopted by Shigeo as part of the Toyota Production System
-- He asserts that:
 Errors are inevitable in any manufacturing process,
 Mistakes can be caught quickly & prevented from resulting in defects if appropriate poka
yokes are implemented.
 By eliminating defects at the source, the cost of mistakes within a company is reduced. “
Poka Yoke in Services
Service mistake proofing must account for the customer’s activities as well as that of the
producer, and mistake proof methods must be set up for interactions conducted directly or by
phone, mail, or other technologies.
Service poka yokes are classified by the type of error they are designed to prevent: service
errors and customer errors.
Service errors result from the: 1) tasks, 2) treatment, 3) tangibles of the service.
Task errors include:1) doing work incorrectly, 2) doing work in the wrong order, 3) doing work
too slowly, 4) doing work not requested
Examples of poka yoke devices for task errors are: computer prompts, color-coded cash
register keys, measuring tools (such as McDonald’s French fry scoop), & signaling devices.

2. Hospitals use trays for surgical instruments that have indentations for each instrument,
preventing the surgeon from leaving one of them in the patient
Treatment errors arise in the contact between the server & the customer, such as: lack of
courteous behavior, failure to acknowledge, listen or react appropriately to the customer
To promote friendliness of a fast food restaurant, trainers provide the 4 specific cues for when to
smile: 1) when greeting the customer, 2) when taking the order, 3) when telling about the
dessert special, 4) when giving the customer change. They encourage employees to observe
whether the customer smiled back, a natural reinforcer for smiling.
Tangible errors are those in physical elements of the service, such as: unclean facilities, dirty
uniforms, inappropriate temperature, document errors.
Examples to avoid tangible errors: 1) Hotels wrap paper strips around towels to help the
housekeeping staff identify clean linen and show which ones should be replaced; 2) Spell
checkers in word processing software help eliminate misspellings provided they are used!)
Customer errors occur during: 1) preparation, 2) the service encounter, 3) during resolution.
Customer errors in preparation arise when customers do not bring necessary materials to the
encounter, do not understand their role in the service transaction, or do not engage the correct
service.
Customer errors during an encounter can be due to inattention, misunderstanding, or simply a
memory lapse, and include failure to remember steps in the process or to follow instructions.
Poka yoke examples include height bars at amusement rides that indicate rider size
requirements, beepers that signals customers to remove cards from ATM machines, and
airplane lavatory doors that must be locked to turn on the lights.
Customer errors at the resolution stage of a service encounter include failure to signal service
inadequacies, learn from experience, adjust expectations, and execute appropriate post-
encounter actions. Hotels might enclose a small gift certificate to encourage guests to provide
feedback. Strategically placed tray-return stands and trash receptacles remind customers to
return trays in fast-food facilities.
Mistake-proofing a service process requires when and where failures generally occur. Once a
failure is identified, the source must be found. The final step is to prevent the mistake from
occurring through source inspection, self-inspection, or sequential checks.
B. Quality Assurance
 “beginning of line”principle
 procedures are put in place to which people work, and by doing so good quality is
ensured
 proven to be very successful, and has beedeveloped into what is now known as ISO
9000, the world’s biggest selling standard.

3.  ISO is widespread in manufacturing, & in mid 1990companies in Europe started to
apply ISO to the service sector
 ISO (International Standard Organization) – conducts major reviews of its standards
roughly every 5 years. The original standard review was in 1994. The latest version is
BS EN ISO 9001 (2000), with 4 core standards:
1) ISO 9000: Concepts and Terminology
2) ISO 9001: Requirements for Quality Assurance – Toprovide confidence as a result of
demonstration of aproduct/service conformance to established requirements
3) ISO 9004: Guidelines for Quality Management of Organization-To achieve benefits
for all stakeholders through sustained customer satisfaction.
4) ISO 10011: Guidelines for Auditing Quality Management
 Adoption of ISO standard is a prerequisite for doing business in Europe. Asia, Africa &
South America is considering its adoption as means to increase trade among them& w/
the US.
 Benefits of External Quality Standards
Internal benefits
1) defines responsibilities
2) written procedures form a point of reference for all staff
3) reduces cost of failure
4) improves morale & motivation
External benefits
1) Enhances marketability (as some customers only buy from registered suppliers)
2) Enhances customer confidence
3) Enhances image & reputation.
 The revised ISO 9001 (2000) quality standards are based on the following 8 principles:
Principle 1: Customer focus
Principle 2: Leadership
Principle 3: Involvement of people
Principle 4: Process approach
Principle 5: System approach to management
Principle 6: Continual improvement
Principle 7: Factual approach to decision making
Principle8: Mutually beneficial supplier relationship