The Silence of Data
本章では、統計的分析そのものよりも、
数値の持つ構造的意味に焦点を当てています。
Cpkや原価計算、歩留まり改善といった指標は、
単なる改善ツールではありません。
それらは「誰が不可欠なのか」という組織の前提をも可視化します。
本章で桜子たちが行っているのは、
材料比較という技術検討でありながら、
実際には“人に依存した均衡”と“制度に依存した安定”の差を検証する作業です。
数字は感情を持ちません。
しかし、数字は時に、人間の作り上げた構造を静かに否定します。
その沈黙が、ここでは物語の中心になります。
Nishino’s face did not stiffen because of Sakurako’s words.
It was the numbers on the screen that unsettled him.
Two cost structures stood side by side on the monitor.
“…This doesn’t align,” Nishino said quietly. “If we switched to Kokyo Chemical’s material, operator-dependent adjustments would be minimized. Yield improves. Overtime drops. Scrap decreases. Even total cost declines.”
He swallowed.
“There’s no way Manager Yamashita hasn’t run this same calculation.”
Sakurako held the smooth powder sample between her fingers.
Uniform. Dry. Stable.
The data did not require interpretation. It required acceptance.
Switching materials would not increase cost.
It would reduce volatility.
Yet Yamashita continued to protect the humidity-sensitive material—the one that required concessions and midnight interventions.
“Nishino-kun,” Sakurako said softly, “our data has reached its analytical limit. Let’s speak with her once more.”
⸻
The Distorted Equilibrium
In the far corner of Kohaku-tei, Hazuki studied the comparative charts in silence.
“…So it stabilizes at this level,” she murmured. It was not surprise in her voice, but recognition.
“With Kokyo’s material, the line wouldn’t fear humidity. No more overnight adjustments. No more emergency recalibrations.”
“It was never structurally necessary,” Nishino added.
He hesitated.
“Manager Yamashita must know this. So why continue?”
Hazuki stared out into the dark window.
“He does not become agitated during instability,” she said at last.
“He becomes focused.”
She paused, choosing her words carefully.
“When the line falters and everyone else loses composure, that is when he is most precise. He steps in, alone, and restores order through adjustments no one else can replicate.”
“The next morning,” she continued, “the line runs again. And the staff look at him differently.”
Sakurako remembered the sharp discontinuities in the interaction plot.
Perhaps those spikes were not merely statistical artifacts, but recurring events within a predictable pattern.
“Does he maintain instability intentionally?” Nishino asked.
Hazuki shook her head faintly.
“I don’t think it’s intentional in that sense.”
She folded her hands around her cup.
“It’s more that he seems deeply uncomfortable with a system that operates flawlessly without his intervention.”
Silence settled over the table.
“If we adopt this material,” Hazuki continued, “performance would stabilize around the median—regardless of who is present on the floor.”
She looked at Sakurako.
“And in such a system, no one person becomes indispensable.”
The implication did not need to be spoken.
Sakurako felt the outline of something larger emerging.
Perhaps Yamashita’s objective had never been maximum productivity.
Nor was it simple cost control.
It was equilibrium.
But not system equilibrium.
An equilibrium calibrated around one decision-maker.
“Is it about authority?” Nishino asked quietly.
Hazuki exhaled.
“I think it is about existence.”
She lowered her gaze.
“When crises occur, he is needed. When he is needed, he is acknowledged. When he is acknowledged, the structure feels stable—to him.”
Sakurako looked down at the Kokyo report in her hands.
The numbers were clean.
Replicable.
Impersonal.
They offered a system in which no one had to be extraordinary.
“Nishino-kun,” she said at last, her voice steady, “this is not merely a cost-reduction proposal.”
She met his eyes.
“This is a proposal to transition from a person-dependent structure to a system-dependent one.”
Outside, the night remained still.
Inside the café, three engineers sat quietly with a set of numbers that did not accuse anyone—yet quietly threatened an entire equilibrium.
Comprehension Questions
(The Silence of Data – Revised)
Q1.
What is the primary reason Nishino becomes unsettled when reviewing the data?
A. The new material is more expensive than expected.
B. The cost comparison contradicts the current material policy.
C. The yield rate cannot be calculated accurately.
D. The humidity data is incomplete.
⸻
Q2.
According to Hazuki, under which condition does Manager Yamashita appear most composed?
A. When production runs flawlessly without interruption.
B. When cost targets are exceeded.
C. When instability occurs and he can personally restore order.
D. When the warehouse achieves perfect humidity control.
⸻
Q3.
What does Sakurako ultimately identify as the core issue behind the material decision?
A. A lack of statistical expertise.
B. Excessive dependence on supplier contracts.
C. A system calibrated around a single decision-maker.
D. A misunderstanding of interaction effects.
⸻
Q4.
Why would switching to Kokyo Chemical’s material threaten Yamashita’s position?
A. It would increase operational risk.
B. It would reduce his opportunity to intervene and be perceived as indispensable.
C. It would require new staff training.
D. It would eliminate the need for statistical analysis.
⸻
Q5.
Which statement best captures the thematic contrast presented at the end of the chapter?
A. Personal authority is more efficient than system stability.
B. Emotional leadership outweighs numerical precision.
C. Clean, replicable data challenges a person-dependent structure.
D. Supplier loyalty ensures long-term profitability.
製造業において「安定」は最も価値のある状態です。
しかし、安定の形には二種類あります。
一つは、特定の人物の経験や勘に支えられた安定。
もう一つは、誰が担当しても同じ結果が出る仕組みによる安定。
後者を実現するために必要なのは、
華やかな才能ではなく、
再現性と説明可能性です。
本章で示された代替材料のデータは、
単なるコスト改善案ではありません。
それは「個人を中心とした均衡」から
「制度を中心とした均衡」への移行を示唆しています。
組織の成熟とは、
優れた個人を否定することではなく、
その優秀さを“仕組みの中に組み込む”ことです。
