Finishing difficult work can make a favourable explanation feel deserved. A disappointing result can make an unfavourable explanation feel obvious. Put the record on the table before choosing either story.
Write the intended result, the observed result and the supporting evidence. Then list explanations that remain uncertain. Knowing that something happened and knowing why require different kinds of support.
Compare fairly
Suppose a fictional team completes more deliveries after changing its dispatch board. The board may have helped. Routes may also have become shorter, loads smaller or receiving sites more available. Check operating conditions and the measurement boundary before claiming an improvement.
For personal work, avoid judging an entire week by its most memorable hour. Look at commitments kept, decisions improved and relationships affected. Include work that prevented a problem while remaining honest about whether prevention can actually be established.
Choose a learning action
If the evidence cannot distinguish explanations, design a small test that clarifies one. Keep conditions comparable where possible and state what would change your mind.
A review earns its effort when it informs the next decision. You can acknowledge good work without making unsupported claims. You can acknowledge a poor result without treating it as a permanent verdict on ability. Accuracy gives praise, correction and the next attempt something solid to stand on.