Perakende sektöründe stok sınıflandırması ve ürün yaşam eğrisi analizi
Stock classification and product life cycle analysis in retail sector
Yazar: ELVAN PALABIYIK
Danışman: DOÇ. DR. MURAT BASKAK
İstanbul Teknik Üniversitesi / Fen Bilimleri Enstitüsü / Endüstri Mühendisliği Ana Bilim Dalı / Endüstri Mühendisliği Bilim Dalı
Derece: Yüksek Lisans, 2019
Konu: Endüstri ve Endüstri Mühendisliği = Industrial and Industrial Engineering

Özet:
Günümüzde tüketim alışkanlıklarının ve ekonominin hızlı değişimi, rekabet koşullarının artması perakendecilerin müşteri odaklı çalışmalarına yol açmıştır. Bununla birlikte müşterilerin beklentileri, talep ettikleri ürünü uygun yer ve zamanda perakende mağazalarında bulabilmektir. Perakendeciler bu noktada müşteri talebini karşılayacak çeşit, lokasyon ve hız kavramları üzerine yoğunlaşmaktadır. Müşteriye daha yakın olmak daha fazla mağaza sayısına, müşteri ürün talebi ise daha fazla çeşide neden olmaktadır. Tüm bunlar, bir perakendecinin doğru bir tedârik zinciri yapılanmasını beraberinde getirir. Doğru bir tedârik zinciri kurgusu ürün, plânlama, tedârik, depolama, dağıtım ve satış unsurlarının tümünü içerici rol oynamaktadır. Sürdürülebilir bir tedârik zinciri yapılanması için tüm faaliyetlerin senkronize, ölçümlenebilir ve esnek olması beklenir. Etkin bir tedârik zinciri oluşturmanın ilk kuralı, sistemin ana unsuru olan stok birimlerini tanımaktır. Çünkü stoklar hammadde, yarı ürün veya ürün olarak; üretici, tedârikçi veya perakendecide olabilir. Tedârik zinciri mâliyetlerinin en büyük bileşeni olan stokların işletme tarafından ayrıntılı ölçümlenmesi ve izlenmesi, işletmenin firmalar arası rekabet gücünü arttırır. Stokta taşıdığı ürünlerin ayrıntılı bilgisine sahip olan tüm firmalar, varolan sistemdeki iyileştirme olanaklarını ve gelecek yatırımlarını daha doğru plânlayabilir. Bu çalışmanın amacı; tedârik zincirinin ana kavramı olan stok birimlerinin kontrol edilmesini içerir. Faaliyet alanlarına göre işletmelerde farklı şekillerde bulunan stok, bir perakende firmasının varlığını oluşturması için gerekli olan ilk yatırım olarak düşünülebilir. Çünkü perakendeci firmalar, bir ürünün doğrudan nihaî tüketiciye sunulduğu işletmelerdir. Bir perakendeci, tüketicisine sunduğu ürün çeşitliliği ölçüsünde varlığını sürdürebilir. Müşteri talepleri ve rekabet nedeniyle, perakendeciler yeni ürünler sunmaya zorlanırlar ve aynı zamanda eski ürünleri durdurmak için karar almak konusunda da isteksiz davranırlar. Tüm bu talepler, ürün yelpazesinin genişlemesine, ürün ömürlerinin kısalmasına ve stokta yığılmaya neden olur. Böylece stok mâliyetlerinin buna bağlı artışı kaçınılmazdır. Kısıtlı malî kaynaklar içinde şirketlerin optimal yararı sağlayabilmesi için etkin bir stok ve envanter kontrolü gereklidir. Bu çalışmada bir perakende firmasının incelenen ürün karması stok sınıflandırılması, ürün yaşam eğrisi ve portföy analizi kavramları ile incelenerek, âtıl ürünlerin sistemden çıkarılması için öneri işaretlemeler yapılmıştır. Giriş bölümü sonrası ikinci bölümde konu ile ilgili literatür araştırması yapılmıştır. Üçüncü bölümde perakendecilik, perakendeciliğin yeri ve mağaza tipleri; dördüncü bölümde ise perakende firmasında ürün yönetim başlıkları incelenmiştir. Beşinci bölüm stok, stok tipleri, stok mâliyetleri ve stokların sınıflandırılması kavramlarını içerir. Altıncı bölümde ilgili perakende firmasının envanter kayıtları ve satış verileri ABC/XYZ sınıflandırması, ürün yaşam eğrisi ve BCG porftföy analizi yöntemleri ile incelenmiştir. Ulaşılan bulgular ile perakendeciye etkin ürün portföyü yönetimi için destek vermek amaçlanmıştır.

Abstract:
Nowadays, the rapid change of consumption habits and the economy, and the increase in the competition conditions have led to customer-oriented efforts of retailers. In addition to that, the expectations of the customers are finding the products in the right place, at the right time in retail stores. At this point, retailers focus on the concepts of variety, location and speed to meet customer demand. That, being closer to the customer leads to more numbers of stores and customers product demand leads to more variety. All these lead to the establishment of a proper supply chain structure by a retailer. An accurate supply chain structure plays an integral role in all the product, planning, procurement, storage, distribution and sales. All activities are expected to be synchronized, measurable and flexible for a sustainable supply chain structure. The first rule of establishing an effective supply chain is to recognize the stock units, which are the main elements of the system. Because stocks will be raw materials, semifinished products or finished goods; the manufacturer, supplier or retailer. The detailed measurement and follow-up of the inventories, which are the biggest component of the supply chain costs, increases the competitiveness of the firm. All the companies that have detailed knowledge of the products, which they carry in stock, can plan the improvement opportunities in the current system and their future investments more accurately. The aim of this study is to control the stock units, which is the main concept of the supply chain. The stock, which is in different forms in the enterprises according to the fields of activity, can be considered as the first investment necessary to create the existence of a retail company. Because retailers are companies where the product is offered directly to the final consumer. A retailer can survive to the extent of product variety offered to its consumers. Due to customer demands and competition, retailers are forced to offer new products and are also reluctant to make decisions to stop old products. All these demands lead to a widening of the product range, shortening of product life and accumulation in stock. Thus, the increase in inventory costs is inevitable. An effective inventory control is required for companies to achieve optimal benefits in limited financial resources. In this study, stock classification, product life cycle and portfolio analysis were made for the product mix of a retail company and suggestions markings were made for the removal of the inert products from the system. In the second part of the study, literature research has been carried out in the titles of classification of stocks, field management and product selection in retail sector, portfolio contraction and delist concept, and product life cycle. Generally, the classification of stocks studies includes the multi criteria classification examples suitable for the working sector. Most of the study is worked on large amount of SKU, as supermarket products or pharmacy goods. Field management and product selection in retail sector studies are especially worked as optimizing problem. They are concentrated on placing right SKU to right shelf or right category the place for maximizing margin or sales data. These studies didn't contain the removing or delist the SKU's. Portfolio contraction and delist concept studies are totally concentrated on portfolio. They include all the SKU data for selecting the most suitable SKU's for study sector. Their main aim is marked the removing or delisting SKU's. Product life cycle studies examined on life cycle stages and they are focused on what retailer should do on these stages. The studies encountered in the literature research show how important the correct stock, right product management and optimizing, is the priority for each period in each sector group. The third section includes retailing, aim of retailing, the classification of the retailing, also current conditions of the retail market on global. Retail means that the sale of goods to the public in relatively small quantities for use or consumption rather than for resale. It will be classified as types, sizes, locations, ect. Commonly, they are classified according to operation methods, like store based and non-store based. Store based format include all the retail stores like supermarket, hypermarket, discount markets, etc. Non-store retail organizations focus on establishing direct contact with the consumer. The fourth part of the study includes retail product management issues. In this section, the concepts of category management, in-store space management, supplier management in relation to inventory and product management, are explained. Product life cycle and portfolio analysis concepts are emphasized. Category management is the process of managing retail business that merchandise category outputs rather than the contribution of individual brands or models. Under category management retailer's efforts (promotional, pricing and display) are grouped into categories with the objectives of measuring their financial and marketing performance separately. Space management involves the management of a stores physical space inventory. The importance of managing store floor space, retailers only need to consider the fact that pay per square meter for the shop space that rent. It would thus be in best interest to manage it properly and ensure maximum financial return on the space that occupy. Supplier management refers to all the business processes and activities that deal with the entire lifecycle of a supplier for an organization. It includes supply chain, product specifications, logistic and contract management. Product management is an organizational lifecycle function within a company dealing with the planning, forecasting, and production, or marketing of a product or products at all stages of the product lifecycle. Similarly, product lifecycle management (PLM) integrates people, data, processes and business systems. It also includes pricing, branding, marketing activities. In the fifth section, stock which is the main problem of the study, is detailed the subject of stock, the concepts of stock, stock types, stock criteria and stock costs. Also, inventory classification control methods are explained as single and multiple criteria. Stock means that the goods or merchandise kept on the premises of a shop or warehouse and available for sale or distribution. It will be classified as types, sizes, color, nature of business. Inventories are also classified as merchandise and manufacturing inventory. Other such classifications on various bases are goods in transit, buffer stock, anticipatory stock, decoupling inventory, and cycle inventory. Inventory costs are all costs associated with ordering, holding and managing the inventory or stock of an operation or business. These inventory costs include ordering costs, holding costs, and shortage costs. Inventory classification control analysis will be single criteria as ABC, XYZ, VED, GLOF, etc. or it will be controlled with multi criteria as matrix chart. The sixth chapter involves working on the data of a large-scale retail company. The retail company, is a food retail chain spread across the country, serving as supermarkets, hypermarkets and grocery stores. It manages approximately 50,000 SKU's of product mix, not only food products but also non-food products. The company performs category management in order to facilitate the management of products on SKU basis and to increase customer satisfaction, sales efficiency and operational efficiency. Store area management in the company is carried out with the planograms formed by grouping the products with similar category or customer demand in the same direction for the shelves. In this study firstly all the categories had been controlled. Then two group categories, which include substitutable SKU's and have seasonal effects, are selected for study. These categories are dishwasher detergents and water- mineral water category groups. Then, group data were analyzed for 4 years, each SKU entered into stock or sold once during this period was marked and included in the study.  In the study, product groups belonging to selected categories of retail company were examined by ABC / XYZ stock classification method. Then, the products in CZ group which are low efficiency, difficult to predict and low continuity products, is detailed with product life cycle graphs were drawn. The product life cycle graphs have shown that some products have similar curves. Accordingly, four groups of products with similar characteristics were separated. These are delisted products, delist offer products, campaign products, new products and other products. Delist products are presumed to be product groups which are not actively sold and stocked by the company, but are not fully out of stock, have not been returned to the company or returned as per the agreement. Delist offer products have been constantly fluctuating in their life time but have not achieved large turnover. These products are taken out of the system; It may be advantageous for the retailer to offer new products in the areas they occupy. Campaign products; is the group that was purchased and sold by the company for the campaign period only, not fed with new stock, having low inventory but intensive sales graph for the period it entered in to sales, and therefore the demand variability is high. New products are newly listed by the company and have just entered the product mix. Demand balances did not occur because their time on the shelf was limited. For this group, which is at the beginning of the product life cycle, there is no intensive stock in the company shelves. Other products can be considered as delist products. Demand curves have been variable in all life span. However, unlike the previous product groups, they had higher turnovers in certain periods, but they were not followed-up as campaign products. In addition, the products of the main category were analyzed by BCG portfolio analysis and the inferences were compared with the life cycle predictions. In the study conducted in the category of water and mineral waters, it was found that many products belong to the same brand while forming a delist group of products. In order to measure the relationship of the products in this class with the existing brand conditions, BCG matrix was applied on brand basis for water and mineral water class and it was seen that the brand-based values of the products delist for the relevant period were in the problem group. As a conclusion, to the advantage of the company; the delist suggestion group and the other product group, which constitute 14% of the total SKU number of which sales and orders are in progress, were presented as products that the company could terminate the work and take out of the system and enable it to offer new products in the areas they cover. As a result of the necessary research and analysis, reviewing the product groups determined in line with the sales targets of the firm shows that it has a positive effect on stock costs and stock management.