Why is consistently relying on last-click attribution inherently problematic for accurately evaluating Bing Ads campaign effectiveness?

Consistently relying on last-click attribution is inherently problematic for accurately evaluating Bing Ads campaign effectiveness because it unfairly credits the final ad interaction before a conversion while completely ignoring the influence of all prior touchpoints in the customer's journey. Last-click attribution gives 100% of the credit for a conversion to the last ad a user clicked on before converting, regardless of how many other ads they saw or clicked on previously. This approach creates a skewed view of campaign performance by undervaluing or completely dismissing the contributions of earlier ads that played a crucial role in introducing the product, building awareness, or nurturing the lead. For example, a user might initially click on a broad keyword ad that introduced them to a brand. They then research the product further over several days, clicking on several other ads, before finally converting after clicking on a branded keyword ad. Last-click attribution would only credit the branded keyword ad, even though the initial broad keyword ad was instrumental in starting the customer journey. Consequently, campaigns focused on top-of-funnel activities or brand awareness are often unfairly penalized under last-click attribution, leading to misguided budget allocation decisions and an inaccurate understanding of which ads are truly driving conversions. This can result in underinvestment in valuable early-stage campaigns and over-investment in late-stage campaigns, hindering overall marketing effectiveness. More sophisticated attribution models, such as linear, time decay, or position-based, provide a more comprehensive view of the customer journey and allow for a more accurate assessment of each ad's contribution to the final conversion.